Best sleep trackers: Fitbit, Withings and top sleep monitors compared

Take control of your sleep with our pick of the elite slumber supervisors
The best sleep trackers
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Good quality sleep is linked to general health, mental wellbeing and even avoiding serious long-term illnesses, so using a sleep tracker to check you're getting enough rest can be a genuine help.

Wellness isn't just about doing cat yoga and drinking alt-milks, sometimes you just need a refreshing sleep.

There are now plenty of different ways to track sleep, whether that's through a bedside monitor, a wrist-worn wearable like a smartwatch or a device that fits under your mattress.

All will give slightly different insights and personalized tips on how to improve your rest time, but the options from our picks below are worth exploring if you want to know exactly how you're sleeping – and make positive steps to improve it.

We'll be breaking down what to look for in a sleep tracker, how it manages to track your sleep accurately and the best sleep gadgets to buy – we've tested them all so you don't have to.

Update: This article was updated in May 2021 to reflect the addition of the Garmin Venu 2

Sleep tracking: Terminology explained

Terminology explained

Before you can pick the right sleep monitor to watch over your night, you need to know exactly what you want from one. The tech involved here is much more advanced than the smartphone apps that use the accelerometer to track movement under your pillow – and, as a result, things are much more accurate.

HR vs. movement sensors

Older fitness trackers used wrist movement to track sleep, but now it's all about heart rate monitoring – and companies like Fitbit and Withings are looking at your beats per minute (bpm) during sleep to make assumptions not only about duration, but which sleep stage you're in. Pretty much every sleep tracker now incorporates heart

Sleep stages

Sleep Stage are tracked by most top sleep monitors, and this means logging the amounts of light, deep and REM sleep plus any awake time – including tossing and turning.

You should cycle through these sleep stages a few times per night to feel rested – and the trackers below will show this in their analysis. If you're not cycling between them – or you're missing out on some of these stages altogether – it's a smoking gun for bad sleep, and a great place to start improving.

Sleep scores

Looking at all this data can feel overwhelming – and when you've looked at the data for a few weeks you'd be forgiven for wondering what it all means.

Many brands now distill your data down into a meaningful number, so you can see how your slumber stacks up. Several of the brands below (Fitbit, Garmin, Withings and Xiaomi) offer a single sleep score from their data.

Blood oxygen and sleep apnea

The latest data in town is blood oxygen – which is tracked using an SpO2 sensor. You'll find them on some Fitbit, Garmin and Withings devices.

That might sound nuts, but the amount of oxygen in your blood – or at least a dip in levels while asleep – is linked to a condition called sleep apnea. It's estimated 22 million Americans suffer with it, and the majority don't actually realize it.

Choosing a sleep tracking wearable with an SpO2 sensor will offer up this data, so you can ensure you're not an unwitting statistic.

The best sleep trackers

We've tested the best sleep trackers on the market, and spent serious time comparing the data. As the data is recorded while you're asleep, it's often hard to verify accuracy. In many ways, it doesn't matter if your tracker is 100% accurate, it's really about trends over time. But we consider these models to be the most accurate.

Fitbit Sense

Price when reviewed: $329.95

Fitbit Sense

When it comes to tech, the Fitbit Sense is the best wearable sleep tracker on the market right now, and we've tested it extensively.

It's light on the wrist and won't get in your way, thanks to that 40mm case size. Even better, it uses the same sleep tracking technology as the rest of the Fitbit line.

Fitbit Sleep Stages mean you can get a daily look at your light, deep, REM and awake times, and you can still check in on how your night compares to the last month and other people your age.

Fitbit Sense data

(The Fitbit app shows sleep history, stage breakdowns and detailed graphs)

The Sense is built with a tri-wavelength HR sensor on board, and uses a relative SpO2 sensor to unlock Estimated Oxygen Variation while you sleep. This is a measure of the oxygen in your blood, and large swings can be a sign of disorders like sleep apnea.

It tracks sleep stages and the time spent in each stage, as well as your heart rate throughout the night and how much you tossed and turned and turn that into a Sleep Score. Fitbit Premium users can see a breakdown of how that score was calculated in more granular detail (see above).

Generally, we've found the Fitbit Sense to produce the most reliable and actionable data of any wrist-based sleep tracker. The data can seem a little harsh, often chopping eight hours in bed down to just six hours of sleep. But you can easily see lifestyle variables in the data better than other sleep trackers.

On the Sense, features like breakdown of duration, sleep stages, heart rate via sleep (plus percentage under resting heart rate) and Estimated Oxygen Variation require signing up to Fitbit Premium.

If you care about your sleep and the other health metrics Fitbit's health watch is capable of delivering, then you'll want in on Premium. In return you'll get something that you can take to bed and get reliable, insightful sleep data.

Wareable verdict: Fitbit Sense review


Withings Sleep/Sleep Analyzer

Price when reviewed: $99.95

Withings Sleep/Sleep Analyzer

The Withings Sleep slips under your mattress and collects your sleep data, and was released back under the company's name after the buy-back from Nokia.

It's not the latest version – the Withings Sleep Analyzer (above) has landed in Europe, but hasn't received FCC approval for its main sleep apnea feature. So if you're in the US, the Withings Sleep is the only option for now.

The Withings Sleep is able to collect data like sleep duration, interruptions, light, deep and REM sleep, plus snoring, thanks to a built-in microphone.

It can tap into the Withings app, giving you a coaching program to help reduce fatigue and improve health. A big new feature addition is that it now has the ability to detect the signs of sleep apnea.

There's not a lot to pick between the sleep mat and Fitbit's wrist-based options in our testing – but we did experience some accuracy issues with the Withings Analyzer when waking up but staying in bed.

Withings Sleep data

Sleep score is a major focus, as it is on most tracking apps now. It's the most obvious way to find out whether you had a good night's sleep, and will be in red if you had a bad night. The higher the score, the better night of sleep you had.

Even better, the app helps you understand what makes a good night of sleep by telling you how to raise your Sleep Score.

The Withings Sleep is the same device as the Nokia Sleep, which we've tested and is the same device with the Nokia name on the front of it. If you want to an idea of what the Withings Sleep is going to be like to use, definitely go have a read of our Withings Sleep Analyzer review.

Fitbit Charge 4

Best sleep trackers: We compare Fitbit, wearable and bedside devices

The Charge 4 also offers the best of the Fitbit sleep tracking experience, and has the same feature set as the Versa 3, including SpO2 blood oxygen monitoring. The only real difference is the form factor.

You get Fitbit Sleep Stages, giving you a more in-depth look at your sleep. It'll track whether you're in light, deep or REM sleep, giving you actionable insights the next morning.

Plus, you can compare your results against people of a similar demographic, as well as your average night's sleep over the past 30 days.

What we like about Fitbit's sleep tracking is that it learns your behavior over time, and will start giving you more and more personalized feedback for getting better rest.

Fitbit Charge 4 sample sleep data

(Fitbit provides sleep overviews, sleep stage breakdowns and a graph)

Tracking accuracy is as good as it gets from the wrist, and the intuitive companion app, where the sleep graphs are held, completes a package that makes this the best fitness tracker for sleep.

Price when reviewed: $149.99

Wareable verdict: Fitbit Charge 4 review

Garmin Venu 2

Price when reviewed: $399.99

Garmin Venu 2

Sleep tracking wasn't exactly one of Garmin's strengths, but it has introduced new Firstbeat algorithms with the Venu 2, and it's proven to be an excellent sleep monitor during our review.

As well as tracking sleep duration, it will also offer a breakdown of sleep stages including REM, deep and light sleep and wake up times. It will distill that all into a single score, and offer a little analysis on how you slept. It's sensitive, and picked up on nights where we'd had alcohol – like the example above.

It will also keep tabs on respiration rate (spikes in the rate can be a sign of illness), stress levels and blood oxygen levels as you sleep.

However, using the Pulse Ox sensor to deliver the latter does have a notable drain on the battery.

Garmin sleep data

It breaks down overall sleep score and rating the different stages of your sleep time. You'll know if you've registered excellent REM sleep time or you recorded a good quality of deep sleep.

As always, you can view sleep trends over period of time to see if there's a pattern to when you often have good or bad sleep and start to correlate that with your training.

However, if you are not quite as advanced as what Polar offers in that respect, but it feels like moves are being made to help show a connection between training and sleep and that all important recovery time.

From an accuracy perspective, the Venu 2 performed well for monitoring bed time and now with additional insights into stress, energy levels and thinking more about the quality of sleep. Garmin is starting dedicate the kind of features to one of the most important aspects of your life when you're not working hard in the gym or putting in lung-busting marathon training.

Wareable verdict: Garmin Venu 2 review


Amazfit GTS 2 Mini

Price when reviewed: $99.99

Amazfit GTS 2 Mini

We’ve highlighted our favourite Amazfit smartwatch here – but the following information goes across the GTS 2 and GTR 2 range – and even applies to the excellent Bip U.

Amazfit’s sleep tracking is extremely detailed when you consider the cost of its smartwatches – and the company has big ambitions when it comes to sleep analysis.

It uses the heart rate sensor to study sleep stages and will track REM, and uses the device’s SpO2 sensor to keep track of blood oxygen at night and offers a sleep breathing quality score.

And it also has a trick up its sleeve: unlike other sleep trackers it will also log naps.

The Zepp app (Amazfit’s companion app) also has loads of insights on sleep, showing your stats for time asleep, deep sleep in context with other users, to try and add context to the data.

Amazfit GTS 2 Mini data

Our only beef with the Amazfit’s sleep tracking is that we feel it generally over-estimates time asleep – possibly due to a lack of sensitivity. For example, if we’re in bed for 8 hours, Withings and Fitbit will usually track 6.5 – 7 hours actual sleep, between tossing and turning. Amazfit usually reports closer to the full 8 hours, and the sleep scores are consequently much better. For our money that makes it less useful – but it’s still fine for establishing trends.

In short, there’s a lot to like and the tracking is better than 90% of budget smartwatches and fitness trackers out there. But it’s not a gold standard device.

Check out our full Amazfit GTS 2 Mini review.


Polar Vantage V2

Polar Vantage V2

The Polar Vantage V2 is a sports watch first and foremost, but it's also a watch that pays close attention to the importance of sleep in relation to recovery and helping you get the most out of your training.

The V2 uses the onboard accelerometer to determine when you're asleep just like other smartwatches and sports watches. It then generates a raft of data and insights.

It will give you a breakdown to show you duration, sleep and awake times plus an overall score for your sleep. It also includes a Nightly Recharge feature that delves deeper into recovery of your automatic nervous system.

sleep trackers update

It was pretty reliable in detecting sleep and wake times in our testing and clocked interruptions as well, while the overall sleep score tended to match how we felt.

These rich sleep tracking features do seem to come at the expense of battery life, based on the kind of drain we saw on the Vantage V2 when we woke up in the morning on check on battery status.

If you can live with charging after around five days as opposed to the seven days Polar promises, in return you'll get more detailed, reliable sleep tracking than Garmin in our experience. It also tries to put your sleep in better context of what it means for your training too. It's also available on cheaper watches like the new Polar Ignite 2 and the Polar Vantage M2 if you want those extra sleep stats for less.

Price when reviewed: $449.99

Wareable verdict: Polar Vantage V2 review


Whoop Strap 3.0

Whoop Strap 3.0

The Whoop Strap 3.0 is a completely different proposition. First and foremost it's a workout tracker, which can be worn in multiple locations and is the choice of CrossFitters and functional fitness types for tracking hardcore sessions.

But while you can read about those aspects in our best gym trackers round up, sleep tracking is also a huge part of the Whoop Strap 3.0's make-up.

A bit like the Oura, the Whoop Strap 3.0 will assign a sleep quality score based on the duration of your sleep measured against your prescribed ‘sleep need', which is based on training and your rest across the week.

It also does the usual stuff: sleep stages such as REM and deep sleep.

Best sleep trackers: We compare Fitbit, wearable and bedside devices

And you can also factor in things like caffeinated or alcoholic drinks, screen time and whether you shared your bed.

This is all used to advise you when to train, and when to take a day off. This is presented with a single number – your Strain Score.

Of course, this isn't a band for those looking to take a few more daily steps (it doesn't actually track steps at all) – but for seasoned gym-goers it's the best option on offer.

It costs more than your average Fitbit though. There's a $25 per month subscription, with a minimum term of six months – but you do get the Whoop Strap 3.0 for free.

Wareable verdict: Whoop Strap 3.0 review

Withings Steel HR Sport

Withings Steel HR Sport

The first watch back under the Withings brand is also able to track your sleep, with the Steel HR Sport providing awake, light and deep sleep times, as well as giving you a look at how your heart rate varies through the night.

The new more health-focused Withings ScanWatch hybrid has recently launched in the UK and Europe, but is still on hold in the US. So we've picked the one that's easier to get hold of and monitor bedtime in a sleeker fashion.

Unless you’re someone who hates having anything on their wrist in bed, the Steel HR Sport’s slim physique makes it comfortable to wear to sleep. There’s an alarm as well, so you can be woken by a gentle vibration on your wrist, instead of a blaring noise.

sleep trackers update

In our testing, accuracy wasn't perfect, but it's not terribly far from Fitbit's standard. The data is easy to digest, as shown above, but sadly the insights aren't quite as meaty as we'd like. However, if you're looking for something that's good at the basics when it comes to sleep, the Steel HR Sport is by no means a bad call.

What you'll get with the ScanWatch over other Withings hybrids is an SpO2 sensor, which can unlock the ability to potentially detect signs of sleep apnea. Unfortunately, it's not been approved to do that just yet, so it's not a sleep feature you're missing out on and you'll get as rich an experience from the Steel HR.

Price when reviewed: $329.99

Wareable verdict: Withings Steel HR Sport review


Xiaomi Mi Band 6

Price when reviewed: $59.99

Best sleep trackers: Fitbit, Withings and top sleep monitors compared

The competition for king of the budget fitness tracker band is heating up and the Xiaomi Mi Band 6 while not hugely different from the Mi Band 5, is still a solid performer when it comes to getting into bed.

Sleep monitoring is done automatically giving you the lowdown on time spent in different sleep stages, time slept and can even keep track of naps. It can now also track breathing during sleep using the same optical sensor used to generate heart rate readings during that sleep time too.

While data isn't viewable on the Band itself you can get quite a comprehensive breakdown in the companion phone app where you'll see details on sleep quality, sleep scores and even compare sleep stats to other Mi Band users in your age group.

Best sleep trackers: Fitbit, Withings and top sleep monitors compared

Against a Fitbit Sense, it generated slightly longer periods of sleep, though in general sleep stages were largely in line. It did have some issues picking up REM sleep though did match sleep breathing captured on Fitbit's smartwatch. We should also mention that enabling that REM sleep tracking comes at the detriment of battery life you can expect to get from the Mi Band 6.

Xiaomi will also do a good job of making it very obvious when you've had a good or terribly bad night of sleep and offers sleep summary that's easy to absorb and start to make better sense of your bed time.

Of the budget bands with sleep tracking skills we've tested the Mi Band 6 offers some of the most rewarding results that will be good enough for most.

Wareable verdict: Xiaomi Mi Band 6 review


Apple Watch Series 6 and SE

Price when reviewed: From $279.99

Apple Watch Series 6 and SE

With the arrival of watchOS 7, the Apple Watch does now offer native sleep tracking. That support has been added to the Series 3, 4, 5 and the new Series 6 and SE watches.

That means you no longer have to rely on third party apps to track your slumber. What you will now get with compatible Watches are details on how long you slept, showing dark and light periods for any time you woke up in the night.

It works alongside a new BedTime feature that brings iPhone and Watch closer together to make sure you get to bed on time and wake you up in the morning too.

It's simple but accurate, and in our testing usually matched Fitbit minute for minute with unwavering reliability. It's just the detail that doesn't match up.

Apple Watch sleep data

It's a little more basic than what you'll find on Fitbit's watches or other sleep monitoring watches for that matter.

So if you still want some richer insights, there are still a bunch ofApple Watch sleep tracker apps in the App Store you can make use of until Apple decides to beef up its own offering.

That being said, the Apple Watch is a comfortable smartwatch to wear to bed. Again, not quite as light or small as the Fitbit options – even if you get the 38/40 mm variation – but not a device that feels alien to keep on. And that's especially true if you're wearing a light band, such as the sporty silicon or knitted loops.

And then there's also everything else to consider with buying an Apple Watch – this is comfortably the best overall smartwatch you can buy in 2020.

Wareable verdict: Apple Watch Series 6 review | Apple Watch SE review

Fitbit Inspire 2

Price when reviewed: $99.99

Fitbit Inspire 2

A third and final entry for Fitbit, we’ve added the Inspire 2 because it’s a powerful sleep tracker and its thin and light design makes it super comfortable to wear to bed.

You get the full sleep tracking experience, with sleep stages, restoration, heart rate and sleep score all provided – but you don’t get Estimated Blood Oxygen Variation because there’s no SpO2 on board. You still get those silent alarms to wake you up gently in the morning.

Fitbit Inspire 2 data

Additional insights such as sleep heart rate and your restlessness during the night require a subscription to Fitbit Premium.

Elsewhere it’s the same solid Fitbit experience – just in a smaller, thinner and cheaper package.

Check out our Inspire 2 review


Oura Ring

Price when reviewed: From $299.95

Oura Ring

While a smart ring may be not be the first device you'd think of, the Oura Ring is a powerful and discreet sleep tracker that's well worth serious consideration.

It's packed with sensors including optical heart rate, accelerometer, gyroscope and body temperature sensors.

Oura Ring data

This gives it unique insights into your sleep that rivals in this list can't offer, and it's all geared to two main areas: readiness and sleep.

Based on your sleep score, Oura provides you with a simple, intuitive readiness score for the day. That's based on more than just sleep, including heart rate variability and activity data too. It's one of the most complete biometric trackers out there, and has been in trials for Covid-19 detection.

Oura comes in two models and ring sizes US6 – US13. The second iteration of the smart ring is significantly slimmer and sleeker than its predecessor.

Wareable verdict: Oura Ring review

Beddit 3.5 Sleep Monitor

Price when reviewed: $149.99

Beddit 3.5 Sleep Monitor

Apple-owned Beddit is one for iOS users who really want to get focused on sleep insights. It tracks sleep time, heart rate, breathing and snoring, plus bedroom temperature and humidity.

It does this from under the mattress, using a 2mm thick sensor – so there’s nothing to wear, and it can’t be detected.

The ability to track ambient conditions is one big benefit of Beddit over wearables, and things the temperature can really affect how restful your sleep can be.

You get weekly reports on your sleep, and it works with the Apple Watch to nudge you when it’s time for bed.

The Beddit 3.5 is a good system, but it’s a couple of years old now. We’d certainly recommend the Withings Sleep Analyzer (or Withings Sleep in the US).