The Best Sleep Trackers: Rings, Watches, and Other Wearables

As a writer on Wirecutter’s sleep team, I test gear related to living more comfortably and getting a better night’s sleep, including ergonomic seat cushions and body pillows.

To understand the various components and accuracy of sleep trackers, I did the following:

• I spoke with Clare Varellas and Nikki Rothberg, from Apple’s PR team focused on health, and Kristen Holmes, VP of performance science at Whoop.
• I talked with Oura representatives, including product manager Caroline Kryder; Rebecca Robbins, PhD, a member of Oura’s Medical Advisory Board and instructor of medicine at Harvard Medical School; and Jason Russell, the VP of consumer software product.
• I consulted Seema Khosla, MD, the medical director at the North Dakota Center for Sleep.
• I wore a fourth-generation Oura Ring for six months, tracking my sleep and health data almost continuously. Before that, I wore an Oura Ring Gen3 for about a year.
• Like all Wirecutter journalists, I review and test products with complete editorial independence. I’m never made aware of any business implications of my editorial recommendations. Read more about our editorial standards.
• I chose the experts I consulted for this article for their knowledge and independence. For transparency and accuracy, we have disclosed any affiliations that experts have with companies mentioned in this article.

I also read dozens of journal articles and peer-reviewed research ranging in topic from sleep anxiety and orthosomnia to consumer habits in relation to sleep technology.

Wearable sleep trackers are great for people who have a healthy curiosity about what happens when they sleep and want concrete guidance on how to improve their sleep. Whether you want to optimize your rest to maintain peak athletic performance throughout the day, or you just need a nudge to get off TikTok and into bed, a sleep tracker might help.

Sleep trackers typically log the time and duration of your sleep, how much time they see you spending in each sleep phase (such as REM or deep sleep), and how often you wake or move during the night.

Many such devices double as fitness trackers or smartwatches and also track movement and activity and a range of other metrics, including heart rate, heart-rate variability (HRV), body temperature, blood-oxygen rate, and menstrual cycles. An accompanying app delivers analyses of your sleep and activity levels, which the app often frames as “scores,” along with recommendations for improvement.

If you’re only mildly curious about your sleep and don’t want to commit to an expensive device, start with a free or modestly priced sleep-tracking app. And if you struggle with sleep anxiety (that feeling like you have a 5 a.m. flight every morning), you may want to avoid sleep trackers altogether: A 2017 article in the Journal of Clinical Sleep Medicine suggests that sleep trackers, in causing some people to self-diagnose or seek treatment for perceived sleep problems, encourage orthosomnia, “a perfectionistic quest for the ideal sleep in order to optimize daytime function.” Some recent reporting suggests that tracking can exacerbate anxiety, too.

Seema Khosla, MD, advises understanding the different sleep stages before jumping into your data: “Each sleep stage has its own job,” she said. There’s no need to panic if you got, say, only three hours of “deep sleep” before a job interview.

Sleep trackers can be a helpful learning tool, but they don’t replace medical care. If you have insomnia, sleep apnea, or any other kind of sleep-related disorder, see a medical professional. If your doctor says that using a sleep tracker is a good idea, go for it.

Furthermore, sleep-tracking wearables aren’t always precise: Many calculate sleep and other factors inaccurately due to their reliance on actigraphy, a technology that measures movement. For example, in our tests, one tracker assumed that a tester was sleeping when they were actually awake but lying still. For medically accurate sleep-tracking data, a polysomnography test is the best way to go.

With that in mind, we sought out wearables that had third-party validation studies of earlier generations; all of the options we recommend in this guide had validation studies that we easily found online. Third-party validation studies offer a level of commitment to accuracy and transparency from the company behind a sleep tracker, even if the studies are funded by the company itself.

For this guide, we focused on what would make a sleep tracker most worthwhile for both a health-tracking aficionado and a curious novice, namely comfort and accuracy, as well as ease of use and data comprehension. After identifying five popular sleep and fitness trackers, we convened a testing panel of five volunteers (men and women ranging in age from mid-20s to mid-40s) with different lifestyles and sleep styles, including those with sleep partners, people with children or pets, snorers, and light and heavy sleepers.

Each volunteer tested one or two sleep trackers for three nights each while using a separate heart-rate sensor as a control. Each tester kept a daily sleep log noting their activity the day prior, the quality of their sleep, and their energy levels upon waking.

Throughout our testing, we aimed to answer the following questions:

How well does the sleep tracker log sleep and health data?

Commercial sleep trackers aren’t medical devices, but a good sleep tracker should be able to accurately capture and assess how your heart rate, energy output, blood-oxygen level, body temperature, and other metrics affect — and dictate — the quality of your sleep. For example, each company was excited to tell me about its device’s heart-rate monitoring capabilities, so we put the devices to the test by asking our panelists to wear a Polar H10 heart-rate sensor in conjunction with a sleep tracker each night; we then compared the two data sets and disqualified any trackers that were completely off the mark. We also asked testers to fill out a daily sleep journal with how they were feeling and their sleep and wake times to see if the companion app’s findings seemed accurate.

How well does it track activities?

Our testers wore their sleep trackers all day, not just at night, as activity closely informs rest and recovery. We noted when a tracker mistook cycling for a jog, for example.

Is the data easy to interpret?

Sleep trackers with useful, contextualized data made the top of our list. We gravitated toward wearables that not only provided the hard numbers but also gave a comprehensive summary of what those numbers meant.

Does it offer actionable, well-rounded advice?

We favored trackers that used data from the previous day’s activities and the previous night’s sleep to make recommendations. If we had hit the gym hard, for instance, we appreciated a gentle nudge to rest up. We also prioritized trackers that adapted guidance to the wearer’s actual habits.

Is it comfortable to wear?

We favored sleep trackers that looked discreet during the day and were lightweight and comfortable enough that we could forget we were wearing them while sleeping.

Does it offer useful extras?

We took note of trackers with apps that offered extra features such as guided meditations, breathing exercises, “bedtime stories,” daily sleep journals, and coaching.

What about data privacy?

We reached out to the companies behind the trackers to learn more about their privacy policies. We noted which companies allowed you to opt out of data sharing and how each company shared personal data internally.

Top pick

The best sleep tracker

Oura Ring 4

This stylish ring tracker offers consistently accurate heart-rate data and easy-to-follow guidance. But it’s expensive, and it sometimes mistakes downtime as sleep.

Buy from Amazon
(price varies by color)

Buy from Best Buy
(price varies by color)

The Oura Ring 4 is ideal for people seeking a discreet, easy-to-use sleep tracker with lots of personalized advice. It is a titanium, wedding-band-shaped device that shines infrared, red, and green LED light beams through your skin to measure your respiratory rate, heart rate, heart-rate variability (HRV), blood-oxygen levels, and body temperature at all times of the day.

It uses those metrics to track your sleep, and an accelerometer logs your activity and movement. It then synthesizes the two chunks of data — your sleep versus your energy output — to give you three daily scores, for Sleep, Activity, and Readiness (meaning your readiness for the day). Oura has added 18 sensors to the Oura Ring 4 hardware, as opposed to the Gen3’s eight sensors, and the new “smart sensing” feature makes sure the sensors are optimized at all times.

It offers the most accurate nighttime sleep data. After nearly two years of consistent testing across the Oura Ring Gen3 and 4 models, our testers have found that Oura’s technology offers the most accurate sleep data. The Oura Ring’s findings aligned with testers’ sleep journals (each tester logged their sleep and wake times, and reported how they felt, before checking the Oura Ring’s findings), and they consistently found that their Sleep score was true to how they felt, whether alert or groggy.

Oura’s validation studies suggest that the company has invested in improving the accuracy of its sleep tracking over time. In a 2021 validation study, the device’s data aligned with a polysomnography (PSG) test 79% of the time, up from just 66% in the company’s 2016 validation study. A 2024 study, conducted by independent researchers with funding from Oura, concluded that the Oura Ring “did not significantly differ from PSG for the measures time in bed, total sleep time, sleep onset latency, sleep period time, wake after sleep onset, time spent in light sleep, and time spent in deep sleep.”

The Oura Ring 4 has improved, recessed sensors that make the ring more comfortable. Oura’s new “smart sensing” algorithm also makes sure the ring’s sensors are optimized and working to find the best signal through your finger’s unique physiology. It pulls data from the sensor with the best window into your health, rather than burning several LEDs at once.

With the recessed sensors (as opposed to the three protruding bumps in the Gen3), the Oura Ring 4 feels more like a real piece of jewelry. One tester regularly forgot she was wearing it.

The Oura Ring 4 comes in several finishes, including silver, brushed silver, black, stealth (a matte black), gold, and rose gold. It’s available in a wide range of sizes, from 4 to 15. Testers found the ring comfortable and easier to coordinate with their clothing and accessories than most wristband-style trackers.

It measures heart rate and heart-rate variability accurately. In our tests, the Oura Ring 4’s smart sensors, located on the interior of the ring, accurately measured heart rate and HRV during activity and rest. When we tested the Oura Ring 4 against a heart-rate sensor, it proved to be the most closely aligned of all the sleep-tracking devices we tried.

The Oura Ring was one of the first smart rings to measure HRV, or the regularity (or irregularity) of the time between pulses. High HRV is generally good; it suggests you’re relaxed and well. Low HRV (when the time between heartbeats is consistent, without much variability) may be associated with physical or emotional stress. During our testing of the Gen3 model, the ring was able to detect my very low HRV while I grieved a death in the family. It also detected low HRV when another tester had a stressful travel day.

Its data is easy to read and digest, and its app is easy to navigate. Like many of the sleep trackers we tested, the Oura Ring throws a lot of data at you in the form of color-coded charts and graphs. The app’s interface presents the most important information first, with a spotlight on your highest score. One tester, who described herself as tech-averse, appreciated that the Sleep score appeared front and center in the app.

The app includes explainers for anything you may not understand. It also has Trends and Reports tabs that help to synthesize all of your collected data: The Trends tab’s graphs show you how your Sleep, Activity, Readiness, and Stress scores have averaged over a week, while the Reports tab gives you that same data clearly in monthly, quarterly, and yearly intervals.

Additionally, in the app you no longer have to tap each score to see its details. Instead you can see your daily scores, your health metrics, and your health trends in three separate tabs: Today, Vitals, and My Health. This arrangement made it much easier for me to interpret my data at a glance.

Its recommendations are personalized and easy to implement. We appreciated the app’s useful behavioral directives. For instance, the Oura Ring 4 tells you when it notices a low-HRV trend and recommends a breathing exercise or meditation, whereas other trackers don’t go the extra mile like that.

Another example: If I woke up feeling groggy, the app might suggest that I enter Rest Mode. Caroline Kryder, product manager and women’s health lead at Oura, explained that the app will encourage Rest Mode if your temperature is elevated, your heart rate looks off, or your body is showing signs of strain. I took it as a delightful cue to head back to Wordle or, even better, go for a nap. Then, when the app had noted that I had logged some downtime, it would nudge me to put my newfound energy into action — in other words, to take a walk. After a while, I started feeling like I had developed better habits with these bits of gentle encouragement, rather than scolding.

Testers also liked its Symptom Radar feature. For example, Oura will tell you when your biometrics (body temperature, respiratory rate, resting heart rate, HRV) show “major signs of something straining [your] body.” Oura notified two testers about biometric strain before either of them felt any symptoms; a day later, they both came down with colds. (Note, however, that Oura says the Symptom Radar feature may not work with preexisting chronic conditions that already cause elevated biometrics. For instance, Oura’s algorithm may accurately detect real change in the body that would typically be identified as illness when it may actually be symptoms of an underlying condition, such as pregnancy.)

We also found that the Oura Ring 4 works with your sleep schedule, rather than trying to change your lifestyle. For example, instead of continually pushing a night owl to go to bed by 10 p.m., the Oura app adapts to their sleep habits to determine realistic bedtime goals.

Its activity tracking has improved. When we tested the Oura Ring Gen3, the old activity-tracking software struggled to categorize certain types of exercise. This time, we were impressed with how the Oura Ring 4 was able to differentiate lifting, walking, and swimming. The Activity tab also helps to track your cardiovascular age, and with the software updates to its Automatic Activity Tracking, you can now track your heart rate and rate zones after adding exercise or movement.

The Oura Ring integrates with the Strava fitness-tracking app and social media platform, but it’s not seamless: You have to be signed in to the Strava app and select the activity you want to track. If accurate workout tracking is important to you, consider the Whoop 4.0 or the Fitbit Inspire 3.

Flaws but not dealbreakers

It sometimes logs rest as sleep. Although we appreciate the Oura Ring 4’s improved activity-tracking ability, we were surprised to find that its smart-sensing capabilities sometimes miscategorized general relaxation or extended focus (say, watching a film) as taking a nap. This made us a little suspicious that it could also be miscalculating our time in bed winding down as time asleep.

It’s expensive, and it’s better with a monthly subscription. The Oura Ring 4 costs $350 to $550 depending on the finish (the technology and features are the same in all finishes). And you get far more useful data and recommendations from the app if you sign up for a subscription, which costs $6 per month or $70 if you pay for the whole year up front.

However, the app is free for new users for one month. And the Oura Ring and the subscription are both eligible expenses for those with an FSA (flexible spending account) or HSA (health spending account), which can soften the blow.

It’s still easy to lose. We found that the Oura Ring 4 was much easier to lose track of than other wearables, as we were more likely to take it off throughout the day to wash our hands, do chores, or shower.

The Oura app for iOS has a Find My Ring feature, which shows the last location your Oura Ring was connected to your phone. But keep in mind that the stated location could be miles from where you last wore it.

Key specs

• Subscription cost: $6 a month or $70 for a year
• FSA/HSA eligibility: for the purchase of the device and the app subscription
• Battery life: up to eight days
• Water resistance: down to 330 feet for up to 12 hours
• Warranty: one year
• Privacy: Oura doesn’t share the personal information it collects from its app or device for advertising and marketing purposes, but it does share your data internally and with certain service providers. If your data is shared internally, the company encrypts and anonymizes it. For details, read more about Oura’s privacy policy.

Best for…

Best for tracking both sleep and activity

Whoop 4.0

This wristband tracker excels at logging both sleep and exercise and provides tons of data, but its interface can be intimidating.

$230 from Walmart

May be out of stock

The Whoop 4.0 is a good choice for people who want to track both sleep and workouts and don’t mind inputting a lot of data into the app. It is a low-profile, screenless, woven wristband tracker that shines LED light on your skin as part of Whoop’s photoplethysmography technology (PPG, used to detect blood-volume levels). The Whoop device then translates the differences in light (absorption and reflection) into changes in blood flow, which is how it calculates heart rate and heart-rate variability. The device also uses an accelerometer to track motion. The accelerometer, the PPG, and the device’s machine-learning models make it possible for the tracker to determine your sleep stages.

It offers accurate sleep and heart-rate data. The Whoop 4.0 strap’s heart-rate tracking closely aligned with the heart-rate sensor we used for comparison, though not quite as closely as the Oura Ring’s tracking did.

Our testers reported that the Whoop 4.0 strap was accurate as a sleep tracker, as well. “I’ve tried nearly every fitness device,” said our most physically active tester. “Whoop has been the absolute best when it comes to sleep tracking.” Compared with other trackers, the Whoop device more frequently sensed the correct time our tester went to bed and woke up. That same tester noted that one morning, despite counting eight hours of sleep according to her clock, she still felt tired. The Whoop app confirmed that she was low on REM sleep and needed more recovery.

In a Whoop validation study of the Whoop 3.0 strap, the device correctly captured the time spent in various stages 64% of the time, compared with a polysomnography test.

It offers in-depth activity and recovery tracking. The Whoop system tracks more fitness-related metrics than Oura’s platform does. Every morning, you receive a Recovery score, which aims to show how prepared you are to tackle another day or workout. The Whoop app asks you to input your exercise sessions, such as cycling or jogging, directly; it then measures the activity’s strain, via heart-rate detection, to make recommendations, often in painstaking detail.

For example, the app might tell you that you were in “Zone 3” during a workout, meaning you had hit 70% to 80% of your maximum heart rate. Our testers said that data such as this helped them learn in real time whether they were making strides in their fitness or overdoing it.

It’s comfortable and versatile to wear. Our testers found that the lightweight, woven Whoop 4.0 wristband was comfortable to wear all day and during sleep. (In fact, I often forgot to take it off before hopping in the shower.) Though it isn’t as inconspicuous as the Oura Ring, the Whoop strap blended in with outfits more easily than the bulkier Apple Watch Series 8. Some testers liked that during workouts they could wear the strap on their bicep, and it would still collect data.

Flaws but not dealbreakers

It’s labor-intensive. The Whoop app nudges you, in the form of a pop-up, to fill out a daily journal before accessing your scores. (If you want to skip this step and see your scores right away, you can exit out of the journal.) The journal presents questions asking about your daily habits, such as alcohol or caffeine intake, as well as the type of activity you engaged in, like jogging or cycling.

You can curate the questions to make them more specific to your habits and activities. Some of our testers found that the daily-journal questions kept them aware of their habits and helped the Whoop system deliver better analyses. But others found the process onerous and preferred the Oura app’s more passive interface.

It isn’t particularly stylish. Even though the Whoop band comes in numerous colors and patterns, it looks more like an athletic band than a stylish accessory.

The interface can be intimidating. The Whoop app’s interface isn’t as approachable as those of the other sleep trackers we tested, and its language takes some getting used to. The app focuses more on performance and recovery, rather than energy and rest, and is peppered with terms such as “stress,” “strain,” and “impact analysis,” so using it can feel more like having a personal trainer than an encouraging gym buddy.

Accessing guidance in the Whoop app is also more difficult than in the Oura app. For example, if your REM and deep sleep account for less than 35% of your total time in bed, the app doesn’t offer suggestions on the spot; instead, it suggests that you consult a Whoop Coach (powered by AI) to learn how to improve.

It has the most expensive subscription plan. Whoop doesn’t charge for its wristband, but to use it, you have to sign up for a $239 annual subscription (or $399 for two years).

Key specs

• Subscription cost: $239 (one year), $399 (two years)
• HSA/FSA eligibility: for subscription fees and battery packs
• Battery life: up to five days
• Water resistance: down to 32 feet for up to two hours
• Warranty: lifetime
• Privacy: Whoop never sells your personal data. All data captured in the device and app is encrypted. For details, read more about Whoop’s privacy policy.

If you primarily want to track your workouts but are also curious about your sleep: You might like the Fitbit Inspire 3, the top pick in our guide to the best fitness trackers. The wrist-worn Inspire 3 uses heart-rate sensors and motion detectors to track your activity and energy output. Though this touchscreen wearable offered the most accurate fitness tracking, our testers found its sleep tracking inaccurate. One of our testers also said that its recorded sleep time was inaccurate, as it often determined that he was asleep well before he had actually gone to bed.

Without a subscription, the Fitbit app provides your total sleep time and your time spent in each sleep stage, which are two components of your Sleep score. The subscription, which is $10 per month or $80 annually, gives you access to additional sleep data, including other aspects of your Sleep score, such as your general restlessness (time spent tossing and turning) and your sleeping heart rate. Though these are good data points, they are relatively hidden in the Fitbit app in comparison with what you get from the Oura or Whoop app. Considering that the relatively similar Whoop system offers a more holistic view of how your activity and rest interact, we’ve concluded that it’s worth the $240 up-front cost in comparison with the Fitbit system.

For details about Fitbit’s data handling, see Fitbit’s privacy policy.

If you want to save a little money but keep the software upgrades: The Oura Ring Gen3, a former top pick, provides most of the same data as the Oura Ring 4. The app’s software has been updated and is also available to Gen3 users, though the insights afforded by the Oura Ring 4’s 10 additional signal pathways aren’t available. That means no “smart sensing,” or features such as Symptom Radar, fertility and menstruation tracking, and nighttime movement. The Gen3 still charges at the same rate (20 to 80 minutes), offers a battery life of up to a week, and has a one-year warranty. It’s a solid sleep tracker, but we think the Oura Ring 4 is worth the upgrade considering that you would save only about $50 or so with the Gen3, depending on the finish.

Apple Watch Series 8: Our testers liked how intuitive the Apple Watch was to use and how seamlessly it interacted with other Apple devices. However, it proved uncomfortable to wear while our testers were sleeping, and it did not always accurately measure their time spent sleeping, according to our testers’ sleep journals. At $400, it doesn’t make sense as a purchase just for sleep tracking.

Garmin Venu Sq 2: Our testers also found this Garmin watch uncomfortable to wear to bed. Plus, it sometimes struggled to determine the difference between rest and actual sleep; in one instance, it inaccurately told a tester that she was still asleep when she was actually lying in bed and on her phone.

This article was edited by Christina Colizza and Marguerite Preston.

As a writer on Wirecutter’s sleep team, I test gear related to living more comfortably and getting a better night’s sleep, including ergonomic seat cushions and body pillows.

To understand the various components and accuracy of sleep trackers, I did the following:

• I spoke with Clare Varellas and Nikki Rothberg, from Apple’s PR team focused on health, and Kristen Holmes, VP of performance science at Whoop.
• I talked with Oura representatives, including product manager Caroline Kryder; Rebecca Robbins, PhD, a member of Oura’s Medical Advisory Board and instructor of medicine at Harvard Medical School; and Jason Russell, the VP of consumer software product.
• I consulted Seema Khosla, MD, the medical director at the North Dakota Center for Sleep.
• I wore a fourth-generation Oura Ring for six months, tracking my sleep and health data almost continuously. Before that, I wore an Oura Ring Gen3 for about a year.
• Like all Wirecutter journalists, I review and test products with complete editorial independence. I’m never made aware of any business implications of my editorial recommendations. Read more about our editorial standards.
• I chose the experts I consulted for this article for their knowledge and independence. For transparency and accuracy, we have disclosed any affiliations that experts have with companies mentioned in this article.

I also read dozens of journal articles and peer-reviewed research ranging in topic from sleep anxiety and orthosomnia to consumer habits in relation to sleep technology.

Wearable sleep trackers are great for people who have a healthy curiosity about what happens when they sleep and want concrete guidance on how to improve their sleep. Whether you want to optimize your rest to maintain peak athletic performance throughout the day, or you just need a nudge to get off TikTok and into bed, a sleep tracker might help.

Sleep trackers typically log the time and duration of your sleep, how much time they see you spending in each sleep phase (such as REM or deep sleep), and how often you wake or move during the night.

Many such devices double as fitness trackers or smartwatches and also track movement and activity and a range of other metrics, including heart rate, heart-rate variability (HRV), body temperature, blood-oxygen rate, and menstrual cycles. An accompanying app delivers analyses of your sleep and activity levels, which the app often frames as “scores,” along with recommendations for improvement.

If you’re only mildly curious about your sleep and don’t want to commit to an expensive device, start with a free or modestly priced sleep-tracking app. And if you struggle with sleep anxiety (that feeling like you have a 5 a.m. flight every morning), you may want to avoid sleep trackers altogether: A 2017 article in the Journal of Clinical Sleep Medicine suggests that sleep trackers, in causing some people to self-diagnose or seek treatment for perceived sleep problems, encourage orthosomnia, “a perfectionistic quest for the ideal sleep in order to optimize daytime function.” Some recent reporting suggests that tracking can exacerbate anxiety, too.

Seema Khosla, MD, advises understanding the different sleep stages before jumping into your data: “Each sleep stage has its own job,” she said. There’s no need to panic if you got, say, only three hours of “deep sleep” before a job interview.

Sleep trackers can be a helpful learning tool, but they don’t replace medical care. If you have insomnia, sleep apnea, or any other kind of sleep-related disorder, see a medical professional. If your doctor says that using a sleep tracker is a good idea, go for it.

Furthermore, sleep-tracking wearables aren’t always precise: Many calculate sleep and other factors inaccurately due to their reliance on actigraphy, a technology that measures movement. For example, in our tests, one tracker assumed that a tester was sleeping when they were actually awake but lying still. For medically accurate sleep-tracking data, a polysomnography test is the best way to go.

With that in mind, we sought out wearables that had third-party validation studies of earlier generations; all of the options we recommend in this guide had validation studies that we easily found online. Third-party validation studies offer a level of commitment to accuracy and transparency from the company behind a sleep tracker, even if the studies are funded by the company itself.

For this guide, we focused on what would make a sleep tracker most worthwhile for both a health-tracking aficionado and a curious novice, namely comfort and accuracy, as well as ease of use and data comprehension. After identifying five popular sleep and fitness trackers, we convened a testing panel of five volunteers (men and women ranging in age from mid-20s to mid-40s) with different lifestyles and sleep styles, including those with sleep partners, people with children or pets, snorers, and light and heavy sleepers.

Each volunteer tested one or two sleep trackers for three nights each while using a separate heart-rate sensor as a control. Each tester kept a daily sleep log noting their activity the day prior, the quality of their sleep, and their energy levels upon waking.

Throughout our testing, we aimed to answer the following questions:

How well does the sleep tracker log sleep and health data?

Commercial sleep trackers aren’t medical devices, but a good sleep tracker should be able to accurately capture and assess how your heart rate, energy output, blood-oxygen level, body temperature, and other metrics affect — and dictate — the quality of your sleep. For example, each company was excited to tell me about its device’s heart-rate monitoring capabilities, so we put the devices to the test by asking our panelists to wear a Polar H10 heart-rate sensor in conjunction with a sleep tracker each night; we then compared the two data sets and disqualified any trackers that were completely off the mark. We also asked testers to fill out a daily sleep journal with how they were feeling and their sleep and wake times to see if the companion app’s findings seemed accurate.

How well does it track activities?

Our testers wore their sleep trackers all day, not just at night, as activity closely informs rest and recovery. We noted when a tracker mistook cycling for a jog, for example.

Is the data easy to interpret?

Sleep trackers with useful, contextualized data made the top of our list. We gravitated toward wearables that not only provided the hard numbers but also gave a comprehensive summary of what those numbers meant.

Does it offer actionable, well-rounded advice?

We favored trackers that used data from the previous day’s activities and the previous night’s sleep to make recommendations. If we had hit the gym hard, for instance, we appreciated a gentle nudge to rest up. We also prioritized trackers that adapted guidance to the wearer’s actual habits.

Is it comfortable to wear?

We favored sleep trackers that looked discreet during the day and were lightweight and comfortable enough that we could forget we were wearing them while sleeping.

Does it offer useful extras?

We took note of trackers with apps that offered extra features such as guided meditations, breathing exercises, “bedtime stories,” daily sleep journals, and coaching.

What about data privacy?

We reached out to the companies behind the trackers to learn more about their privacy policies. We noted which companies allowed you to opt out of data sharing and how each company shared personal data internally.

Top pick

The best sleep tracker

Oura Ring 4

This stylish ring tracker offers consistently accurate heart-rate data and easy-to-follow guidance. But it’s expensive, and it sometimes mistakes downtime as sleep.

Buy from Amazon
(price varies by color)

Buy from Best Buy
(price varies by color)

The Oura Ring 4 is ideal for people seeking a discreet, easy-to-use sleep tracker with lots of personalized advice. It is a titanium, wedding-band-shaped device that shines infrared, red, and green LED light beams through your skin to measure your respiratory rate, heart rate, heart-rate variability (HRV), blood-oxygen levels, and body temperature at all times of the day.

It uses those metrics to track your sleep, and an accelerometer logs your activity and movement. It then synthesizes the two chunks of data — your sleep versus your energy output — to give you three daily scores, for Sleep, Activity, and Readiness (meaning your readiness for the day). Oura has added 18 sensors to the Oura Ring 4 hardware, as opposed to the Gen3’s eight sensors, and the new “smart sensing” feature makes sure the sensors are optimized at all times.

It offers the most accurate nighttime sleep data. After nearly two years of consistent testing across the Oura Ring Gen3 and 4 models, our testers have found that Oura’s technology offers the most accurate sleep data. The Oura Ring’s findings aligned with testers’ sleep journals (each tester logged their sleep and wake times, and reported how they felt, before checking the Oura Ring’s findings), and they consistently found that their Sleep score was true to how they felt, whether alert or groggy.

Oura’s validation studies suggest that the company has invested in improving the accuracy of its sleep tracking over time. In a 2021 validation study, the device’s data aligned with a polysomnography (PSG) test 79% of the time, up from just 66% in the company’s 2016 validation study. A 2024 study, conducted by independent researchers with funding from Oura, concluded that the Oura Ring “did not significantly differ from PSG for the measures time in bed, total sleep time, sleep onset latency, sleep period time, wake after sleep onset, time spent in light sleep, and time spent in deep sleep.”

The Oura Ring 4 has improved, recessed sensors that make the ring more comfortable. Oura’s new “smart sensing” algorithm also makes sure the ring’s sensors are optimized and working to find the best signal through your finger’s unique physiology. It pulls data from the sensor with the best window into your health, rather than burning several LEDs at once.

With the recessed sensors (as opposed to the three protruding bumps in the Gen3), the Oura Ring 4 feels more like a real piece of jewelry. One tester regularly forgot she was wearing it.

The Oura Ring 4 comes in several finishes, including silver, brushed silver, black, stealth (a matte black), gold, and rose gold. It’s available in a wide range of sizes, from 4 to 15. Testers found the ring comfortable and easier to coordinate with their clothing and accessories than most wristband-style trackers.

It measures heart rate and heart-rate variability accurately. In our tests, the Oura Ring 4’s smart sensors, located on the interior of the ring, accurately measured heart rate and HRV during activity and rest. When we tested the Oura Ring 4 against a heart-rate sensor, it proved to be the most closely aligned of all the sleep-tracking devices we tried.

The Oura Ring was one of the first smart rings to measure HRV, or the regularity (or irregularity) of the time between pulses. High HRV is generally good; it suggests you’re relaxed and well. Low HRV (when the time between heartbeats is consistent, without much variability) may be associated with physical or emotional stress. During our testing of the Gen3 model, the ring was able to detect my very low HRV while I grieved a death in the family. It also detected low HRV when another tester had a stressful travel day.

Its data is easy to read and digest, and its app is easy to navigate. Like many of the sleep trackers we tested, the Oura Ring throws a lot of data at you in the form of color-coded charts and graphs. The app’s interface presents the most important information first, with a spotlight on your highest score. One tester, who described herself as tech-averse, appreciated that the Sleep score appeared front and center in the app.

The app includes explainers for anything you may not understand. It also has Trends and Reports tabs that help to synthesize all of your collected data: The Trends tab’s graphs show you how your Sleep, Activity, Readiness, and Stress scores have averaged over a week, while the Reports tab gives you that same data clearly in monthly, quarterly, and yearly intervals.

Additionally, in the app you no longer have to tap each score to see its details. Instead you can see your daily scores, your health metrics, and your health trends in three separate tabs: Today, Vitals, and My Health. This arrangement made it much easier for me to interpret my data at a glance.

Its recommendations are personalized and easy to implement. We appreciated the app’s useful behavioral directives. For instance, the Oura Ring 4 tells you when it notices a low-HRV trend and recommends a breathing exercise or meditation, whereas other trackers don’t go the extra mile like that.

Another example: If I woke up feeling groggy, the app might suggest that I enter Rest Mode. Caroline Kryder, product manager and women’s health lead at Oura, explained that the app will encourage Rest Mode if your temperature is elevated, your heart rate looks off, or your body is showing signs of strain. I took it as a delightful cue to head back to Wordle or, even better, go for a nap. Then, when the app had noted that I had logged some downtime, it would nudge me to put my newfound energy into action — in other words, to take a walk. After a while, I started feeling like I had developed better habits with these bits of gentle encouragement, rather than scolding.

Testers also liked its Symptom Radar feature. For example, Oura will tell you when your biometrics (body temperature, respiratory rate, resting heart rate, HRV) show “major signs of something straining [your] body.” Oura notified two testers about biometric strain before either of them felt any symptoms; a day later, they both came down with colds. (Note, however, that Oura says the Symptom Radar feature may not work with preexisting chronic conditions that already cause elevated biometrics. For instance, Oura’s algorithm may accurately detect real change in the body that would typically be identified as illness when it may actually be symptoms of an underlying condition, such as pregnancy.)

We also found that the Oura Ring 4 works with your sleep schedule, rather than trying to change your lifestyle. For example, instead of continually pushing a night owl to go to bed by 10 p.m., the Oura app adapts to their sleep habits to determine realistic bedtime goals.

Its activity tracking has improved. When we tested the Oura Ring Gen3, the old activity-tracking software struggled to categorize certain types of exercise. This time, we were impressed with how the Oura Ring 4 was able to differentiate lifting, walking, and swimming. The Activity tab also helps to track your cardiovascular age, and with the software updates to its Automatic Activity Tracking, you can now track your heart rate and rate zones after adding exercise or movement.

The Oura Ring integrates with the Strava fitness-tracking app and social media platform, but it’s not seamless: You have to be signed in to the Strava app and select the activity you want to track. If accurate workout tracking is important to you, consider the Whoop 4.0 or the Fitbit Inspire 3.

Flaws but not dealbreakers

It sometimes logs rest as sleep. Although we appreciate the Oura Ring 4’s improved activity-tracking ability, we were surprised to find that its smart-sensing capabilities sometimes miscategorized general relaxation or extended focus (say, watching a film) as taking a nap. This made us a little suspicious that it could also be miscalculating our time in bed winding down as time asleep.

It’s expensive, and it’s better with a monthly subscription. The Oura Ring 4 costs $350 to $550 depending on the finish (the technology and features are the same in all finishes). And you get far more useful data and recommendations from the app if you sign up for a subscription, which costs $6 per month or $70 if you pay for the whole year up front.

However, the app is free for new users for one month. And the Oura Ring and the subscription are both eligible expenses for those with an FSA (flexible spending account) or HSA (health spending account), which can soften the blow.

It’s still easy to lose. We found that the Oura Ring 4 was much easier to lose track of than other wearables, as we were more likely to take it off throughout the day to wash our hands, do chores, or shower.

The Oura app for iOS has a Find My Ring feature, which shows the last location your Oura Ring was connected to your phone. But keep in mind that the stated location could be miles from where you last wore it.

Key specs

• Subscription cost: $6 a month or $70 for a year
• FSA/HSA eligibility: for the purchase of the device and the app subscription
• Battery life: up to eight days
• Water resistance: down to 330 feet for up to 12 hours
• Warranty: one year
• Privacy: Oura doesn’t share the personal information it collects from its app or device for advertising and marketing purposes, but it does share your data internally and with certain service providers. If your data is shared internally, the company encrypts and anonymizes it. For details, read more about Oura’s privacy policy.

Best for…

Best for tracking both sleep and activity

Whoop 4.0

This wristband tracker excels at logging both sleep and exercise and provides tons of data, but its interface can be intimidating.

$230 from Walmart

May be out of stock

The Whoop 4.0 is a good choice for people who want to track both sleep and workouts and don’t mind inputting a lot of data into the app. It is a low-profile, screenless, woven wristband tracker that shines LED light on your skin as part of Whoop’s photoplethysmography technology (PPG, used to detect blood-volume levels). The Whoop device then translates the differences in light (absorption and reflection) into changes in blood flow, which is how it calculates heart rate and heart-rate variability. The device also uses an accelerometer to track motion. The accelerometer, the PPG, and the device’s machine-learning models make it possible for the tracker to determine your sleep stages.

It offers accurate sleep and heart-rate data. The Whoop 4.0 strap’s heart-rate tracking closely aligned with the heart-rate sensor we used for comparison, though not quite as closely as the Oura Ring’s tracking did.

Our testers reported that the Whoop 4.0 strap was accurate as a sleep tracker, as well. “I’ve tried nearly every fitness device,” said our most physically active tester. “Whoop has been the absolute best when it comes to sleep tracking.” Compared with other trackers, the Whoop device more frequently sensed the correct time our tester went to bed and woke up. That same tester noted that one morning, despite counting eight hours of sleep according to her clock, she still felt tired. The Whoop app confirmed that she was low on REM sleep and needed more recovery.

In a Whoop validation study of the Whoop 3.0 strap, the device correctly captured the time spent in various stages 64% of the time, compared with a polysomnography test.

It offers in-depth activity and recovery tracking. The Whoop system tracks more fitness-related metrics than Oura’s platform does. Every morning, you receive a Recovery score, which aims to show how prepared you are to tackle another day or workout. The Whoop app asks you to input your exercise sessions, such as cycling or jogging, directly; it then measures the activity’s strain, via heart-rate detection, to make recommendations, often in painstaking detail.

For example, the app might tell you that you were in “Zone 3” during a workout, meaning you had hit 70% to 80% of your maximum heart rate. Our testers said that data such as this helped them learn in real time whether they were making strides in their fitness or overdoing it.

It’s comfortable and versatile to wear. Our testers found that the lightweight, woven Whoop 4.0 wristband was comfortable to wear all day and during sleep. (In fact, I often forgot to take it off before hopping in the shower.) Though it isn’t as inconspicuous as the Oura Ring, the Whoop strap blended in with outfits more easily than the bulkier Apple Watch Series 8. Some testers liked that during workouts they could wear the strap on their bicep, and it would still collect data.

Flaws but not dealbreakers

It’s labor-intensive. The Whoop app nudges you, in the form of a pop-up, to fill out a daily journal before accessing your scores. (If you want to skip this step and see your scores right away, you can exit out of the journal.) The journal presents questions asking about your daily habits, such as alcohol or caffeine intake, as well as the type of activity you engaged in, like jogging or cycling.

You can curate the questions to make them more specific to your habits and activities. Some of our testers found that the daily-journal questions kept them aware of their habits and helped the Whoop system deliver better analyses. But others found the process onerous and preferred the Oura app’s more passive interface.

It isn’t particularly stylish. Even though the Whoop band comes in numerous colors and patterns, it looks more like an athletic band than a stylish accessory.

The interface can be intimidating. The Whoop app’s interface isn’t as approachable as those of the other sleep trackers we tested, and its language takes some getting used to. The app focuses more on performance and recovery, rather than energy and rest, and is peppered with terms such as “stress,” “strain,” and “impact analysis,” so using it can feel more like having a personal trainer than an encouraging gym buddy.

Accessing guidance in the Whoop app is also more difficult than in the Oura app. For example, if your REM and deep sleep account for less than 35% of your total time in bed, the app doesn’t offer suggestions on the spot; instead, it suggests that you consult a Whoop Coach (powered by AI) to learn how to improve.

It has the most expensive subscription plan. Whoop doesn’t charge for its wristband, but to use it, you have to sign up for a $239 annual subscription (or $399 for two years).

Key specs

• Subscription cost: $239 (one year), $399 (two years)
• HSA/FSA eligibility: for subscription fees and battery packs
• Battery life: up to five days
• Water resistance: down to 32 feet for up to two hours
• Warranty: lifetime
• Privacy: Whoop never sells your personal data. All data captured in the device and app is encrypted. For details, read more about Whoop’s privacy policy.

If you primarily want to track your workouts but are also curious about your sleep: You might like the Fitbit Inspire 3, the top pick in our guide to the best fitness trackers. The wrist-worn Inspire 3 uses heart-rate sensors and motion detectors to track your activity and energy output. Though this touchscreen wearable offered the most accurate fitness tracking, our testers found its sleep tracking inaccurate. One of our testers also said that its recorded sleep time was inaccurate, as it often determined that he was asleep well before he had actually gone to bed.

Without a subscription, the Fitbit app provides your total sleep time and your time spent in each sleep stage, which are two components of your Sleep score. The subscription, which is $10 per month or $80 annually, gives you access to additional sleep data, including other aspects of your Sleep score, such as your general restlessness (time spent tossing and turning) and your sleeping heart rate. Though these are good data points, they are relatively hidden in the Fitbit app in comparison with what you get from the Oura or Whoop app. Considering that the relatively similar Whoop system offers a more holistic view of how your activity and rest interact, we’ve concluded that it’s worth the $240 up-front cost in comparison with the Fitbit system.

For details about Fitbit’s data handling, see Fitbit’s privacy policy.

If you want to save a little money but keep the software upgrades: The Oura Ring Gen3, a former top pick, provides most of the same data as the Oura Ring 4. The app’s software has been updated and is also available to Gen3 users, though the insights afforded by the Oura Ring 4’s 10 additional signal pathways aren’t available. That means no “smart sensing,” or features such as Symptom Radar, fertility and menstruation tracking, and nighttime movement. The Gen3 still charges at the same rate (20 to 80 minutes), offers a battery life of up to a week, and has a one-year warranty. It’s a solid sleep tracker, but we think the Oura Ring 4 is worth the upgrade considering that you would save only about $50 or so with the Gen3, depending on the finish.

Apple Watch Series 8: Our testers liked how intuitive the Apple Watch was to use and how seamlessly it interacted with other Apple devices. However, it proved uncomfortable to wear while our testers were sleeping, and it did not always accurately measure their time spent sleeping, according to our testers’ sleep journals. At $400, it doesn’t make sense as a purchase just for sleep tracking.

Garmin Venu Sq 2: Our testers also found this Garmin watch uncomfortable to wear to bed. Plus, it sometimes struggled to determine the difference between rest and actual sleep; in one instance, it inaccurately told a tester that she was still asleep when she was actually lying in bed and on her phone.

This article was edited by Christina Colizza and Marguerite Preston.