Fitbit Charge 3 review

Updated: Still the top fitness tracker – for now
Wareable Fitbit Charge 3
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Fitbit Charge 3
By Fitbit
The Fitbit Charge 3 may be getting long in the tooth, but it's still the leading fitness tracker. We'd encourage readers to look at the Versa smartwatch, Apple Watch or even Amazfit GTS – but if you love the activity band format, it doesn't get better. Sleep tracking is on top of its game, and the Fitbit ecosystem is still first class. You can buy cheaper and thinner – but you can't buy better in this form factor.

  • Decent range of tracked workouts
  • Long battery life
  • Sleep tracking is great
  • No GPS
  • HR sensor laggy
  • Fitbit Pay only in Special Edition

The Fitbit Charge 3 was still the most advanced activity band around, until the Charge 4 dropped in April 2020.

But with smartwatches now packing the same features or not much more money – it's no longer the right choice for everyone.

Check the new band: Fitbit Charge 4 review

Top fitness smartwatches like the Amazfit GTS and Fitbit Versa Lite Edition are all available for around the same cost as the Charge 3 – and the Apple Watch Series 3 costs just a fraction more.

The Charge 3 takes everything that made the Charge 2 great and adds more: a swimproof design, more battery life, a better UI and smarter notifications. It also packs Fitbit’s new SpO2 sensor, which was recently activated having been dormant since the Charge 3's initial release.

So there's now Estimated Blood Oxygen Variation readings available like on more expensive Fitbit devices like the Fitbit Versa 2. This new feature can indicate conditions like sleep apnea.

Due to its age, the Fitbit Charge 3 has frequently appeared on sale, which it makes it a much more tempting prospect.

There’s a lot to unpack in the Charge 3, so let's get to it. We’ve been spending a lot of time with the Charge 3 over the years. Here’s our in-depth updated review.

Update (5 March): Since our initial review, Fitbit has added new features such as Sleep Score, Estimated Bloody Oxygen Variation, and overall refinements to the companion app. We've addressed these in our updated review.

Fitbit Charge 3: Design


If you’ve been paying attention, you’ll have noticed that Fitbit has formalised its design language over the past couple of years. That means hexagons, octagons and a lot more angles.

The Charge 3 follows this trend, but in its favour. Fitbit’s new tracker looks great, with just enough screen to not feel compromised and a band that rarely feels too large.

Which is just as well, because Fitbit only offers the tracker in one size. Different-sized bands, yes, but the core part of the tracker remains the same.

Read this: The ultimate guide to the Fitbit app

The display is 30% larger than that of the Charge 2 (Fitbit does a good job hiding the bezels, but they’re there) and I’ve found this has made it easier to read notifications and skim across the UI. Before slapping the Charge 3 on my arm I was testing the Garmin Vivosmart 4, and the number of accidental presses has decreased dramatically. You can argue that the Alta HR is a nicer looking tracker, but the Charge 3 strikes a better balance between style and practicality.

The Charge 3 walks a fine line between fitness tracker and smartwatch. With more screen space, notifications are much easier to read, while all your fitness data can be viewed on the Fitbit display in a cinch. There’s no broad app ecosystem, but the distinctions between fitness tracker and smartwatch seem to be diminishing.

It also fits great. I’ve been tracking my sleep for almost two years, and not once have I had a problem wearing the Charge 3 in bed. That’s a matter of preference, and for people who do find trackers annoying to wear to bed, the Charge 3 isn’t exactly tiny. But it is light and comfortable, I’ll say that much.

One thing you might have noticed is gone is the side button. Instead there’s a small dimple on the left side of the tracker that functions as a haptic button – and it works a charm.

I’ve found the touchscreen is still a challenge for sweaty fingers, but have had no problem with the haptic button. The swap has allowed Fitbit to make the Charge 3 waterproof, so you’ll now be able to take it swimming. Having spent a couple of weeks with it now, I can assure you that you won't miss the physical button.

Fitbit Charge 3: Health and fitness features


The last two devices launched by Fitbit have been smartwatches – the Ionic and Versa – so you’d be forgiven for wondering why it’s doing a fitness tracker at all. And truth be told, the Charge 3 does a lot of the things you’ll get on those watches.

But Fitbit still sees a market for people who don’t wear watches. Or people who wear (proper) watches and don’t want to replace them, or wear two. But they will wear a fitness tracker on the other wrist.

Because at its heart, the Charge 3 is still fitness, fitness, fitness. Fitbit promises we’ll see the app ecosystem expand in the future, but its Charge devices have always had a laser focus on activity.

The Charge 3 stays on target, supporting a range of fitness modes including running, swimming, cycling, treadmill and strength training. Sure, you can’t play tic-tac-toe on it, but honestly, there’s not a lot that you can do on the Versa that you can’t do here.


One thing that is missing is GPS – and this surprised us. The Charge 3 once again foregoes this feature but can use your phone connection to get that movement data.

This isn’t a deal breaker when you consider the Charge 3’s other limitations compared to a smartwatch; it doesn’t support offline music or LTE. Chances are, you’re not going to take the Charge 3 out for a run without your smartphone, so the lack of GPS – while, again, a tad surprising – isn’t world-ending, even for the serious athletes amongst you.

But in terms of activity it's a well rounded wearable. Not only does it track a broad range of activities (although not what you’d get with a decent Garmin watch) as well as steps, calories, and sleep, Fitbit’s got better at doing so with minimal input.

The Charge 3 once again offers automatic workout detection, and in testing, this has been pretty accurate. For swimming and running, the Charge 3 had no problem detecting what I was doing.

Sleep tracking

As for sleep tracking, the results have been good. I’ve been wearing my Charge 3 to bed most nights, and it continues to be the gold standard for me. Fitbit offers the best platform for sleep tracking out there, and the Charge 3 has all the sensors and data to maximise accuracy and insights.

Sure, some mornings I notice it taking a few minutes more than it should register me being awake, but on the whole it seem to be pretty accurate.


Since the initial release, sleep tracking is the area that has seen the most updates. In addition to the Sleep Stages, Fitbit now includes Sleep Score. This is an easily digestible rating of your previous night's sleep on a scale up to 100. Anything in the 70s is considered 'fair', 80s 'good' and 90s 'excellent'.

Most users will find their sleep averaging between 72 to 83 according to Fitbit. I've never seen mine drop below 70. The Sleep Score rating makes it easier to quantify your night's sleep as well as identify sleep trends at a glance.


The other major addition is Estimated Oxygen Variation. This finally makes use of the SpO2 sensor that was included with the Charge 3 - a first for any Fitbit device. Fitbit stated at the time it wasn't activated and that it would eventually get turned on - but in truth, we didn't expect it would take well over a year.

Essentially, the SpO2 sensor sits alongside the optical heart rate monitor and detects blood oxygen levels while you sleep. This information is useful as high variation can show underlying sleep conditions, such as sleep apnea. Although, Fitbit is careful not to directly make a diagnosis of any conditions – thanks to a lack of FDA clearance. Any major variation in your sleep oxygen level could be a flag to contact your doctor, however.

The sleep insights are also better than the competition, so if you are getting poor sleep scores, the app will offer guidance. And features like setting bedtime reminders do feed into solutions like building sleep consistancy.

Fitbit Premium

Another thing that has changed since the original Charge 3 launch is a new Fitbit Premium service. This costs a month, or a year. This unlocks deeper insight into your Sleep Score, such as your sleeping heart rate as well as how your Sleep Score is calculated.

There are also wellness reports, video workouts in the app and custom challenges. While none of these are necessary for most people, those wanting to dive deeper into their sleep data might be interested in the upgrade.

Charge 3: Heart rate accuracy

So here’s Wareable's co-founder James Stables' readout from a track session, designed to push the sensor beyond its comfort zone, compared with the Garmin Fenix 5 Plus (on top).

The Charge 3 had an average heart rate for the session of 146 bpm compared to 145bpm on the chest strap/Fenix, and a max of 184bpm across both. That's pretty good accuracy. Of course, Garmin does a better job. of accurately plotting hart rates for review, and if you are serious about this kind of data – you should probably look at more prosumer devices than Fitbit offers.


Top: Garmin with chest strap. Bottom: Fitbit Charge 3

But looking back on data is different from the experience of using it out on the track, on the roads, or in the gym.

And actually, the Charge 3 is better at analysing data in the app than it is during a workout.

We still noticed that the sensor lagged behind the chest strap (and the Polar Vantage M optical sensor) during climbing heart rates.

The recorded data is a lot more accurate than it appeared on the wrist, which indicates some lag in processing data on-device, or an issue with the display, that actually caused issues in our testing of the Charge 3.

Fitbit’s algorithms do their work during the sync, and the final results in the app were a little more in tune with the chest strap than what we saw on the Charge 3 screen during our workouts.

So if accurate live readouts are what you’re after (and for many runners, these will be important) the Charge 3 doesn’t deliver as well as we’d hoped.

However, for an overall snapshot of your session, showing how hard you worked, and how many calories you burned, it fares much better.


Reliability issues?

But data can go awry. Here's another set of interval sessions, but one that produced significantly different results: an average difference of 10bpm and much less accurate changes during interval bursts.

Given the results from a new device, this is simply here for transparency. If you really rely on heart rate data, you may need to shoot higher with a Garmin or Polar running watch with an chest strap for high-intensity workouts.


Fitbit Charge 3: Smart features and UI


The Fitbit Charge 3 is blurring the line between fitness tracker and smartwatch by doing its best to impersonate the latter. Notifications is a big one that’s been improved this time, taking advantage of the larger screen to display more information.

The Charge 3 can display notifications from all third-party apps, and the Fitbit app itself will let you toggle the ones you want. This is something that was also a bit broken when I first started testing the Charge 3, but through subsequent updates (one reason we held this review) matters seems to have smoothed out.

The screen is big enough that I’m able to easily read text messages (one of the few things I allow notifications from) and a swipe down on the main clock face will drag down the notification tray.

It’s an advantage over the Garmin Vivosmart 4, for example, where notifications disappear once they’ve been displayed. Here, you can scroll through your history of missed calls, calendar updates and missed messages.

Speaking of, a new feature of the Charge 3 is the swipe-up menu which gives you a look at your fitness progress for the day including steps, distance travelled and (if you’ve synced with your phone since waking up) how many hours you slept the night before.

Again, this is something Fitbit has migrated over from the Ionic and Versa smartwatches. You’ll also see menstrual tracking on the new health dashboard if that’s something you’re tracking.

For Android users, Fitbit has quick replies for incoming messages. This is something we’ve tried on the Fitbit Versa and Ionic and… it’s fine. But as a (currently) iOS user, it’s not something I feel like I’m sorely missing out on.

Since launch, the Fitbit companion app on iOS and Android has had a few facelifts, and the main dashboard has moved from a tile layout to a scrolling list where you can see the most pertinent information about your health and activity. It's a lot cleaner and more refined than before.

You can also add Female Health tracking if you want to monitor your menstrual cycle from within the app but unfortunately, you can't input tracking data from the Charge 3 itself.

Fitbit Charge 3: Battery life

Fitbit promised us seven days of battery life on the Charge 3, and it’s delivered. That’s a couple of days more than the Charge 2, and if you’re not maxing out the exercise modes you’re going to reach that no problem.

It’s still one of Fitbit’s biggest edges over Apple, and the upside of not incorporating GPS is that the connected GPS option drains much less battery. It’s also a reason Fitbit can proudly boast of being an effective sleep tracker.


Fitbit Charge 3: In the landscape of wearables – and the future

The Charge 3 was originally reviewed in October 2018 – so does it make sense to buy it in 2020?

It's still one of the best fitness trackers on the market, thanks to a wealth of sensors, great features, and the newly-activated SpO2 sensor.

If you're reading this, you've probably decided against buying a smartwatch. So if you've made that call, but want top-notch fitness and wellness features, this is still probably your best bet.

We'd recommend an Apple Watch 3 or Versa 2 to most people, but in this form factor, the Charge 3 is still a market leader.

How we test

Hugh Langley


Now at Business Insider, Hugh originally joined Wareable from TechRadar where he’d been writing news, features, reviews and just about everything else you can think of for three years.

Hugh is now a correspondent at Business Insider.

Prior to Wareable, Hugh freelanced while studying, writing about bad indie bands and slightly better movies. He found his way into tech journalism at the beginning of the wearables boom, when everyone was talking about Google Glass and the Oculus Rift was merely a Kickstarter campaign - and has been fascinated ever since.

He’s particularly interested in VR and any fitness tech that will help him (eventually) get back into shape. Hugh has also written for T3, Wired, Total Film, Little White Lies and China Daily.

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