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How to buy the best Fitbit fitness tracker

By Christina Woodger

Our tests have found some brilliant Fitbit fitness trackers, but they’ve also revealed Fitbit trackers that aren’t up to scratch. Read on to find out more.

Put us to the test

Our Test Labs compare features and prices on a range of products. Try Which? to unlock our reviews. You'll instantly be able to compare our test scores, so you can make sure you don't get stuck with a Don't Buy.

From a cheap and cheerful £40 clip-on fitness tracker to a £300 smartwatch, the Fitbit Ionic, Fitbit offers plenty of choice. The best Fitbit devices accurately log your steps, are a breeze to use and are comfortable to wear. 

Whether you want a simple tracker for everyday use, or something more advanced with a heart-rate monitor and smart notifications, we've tested a Fitbit tracker for you. If you simply want to find out which models aced our tests, head to our list of best fitness watches and activity trackers.

But, we’ve also found some Fitbit activity trackers that lagged behind when it comes to accuracy. We’ve uncovered Fitbit devices that reported double the number of calories burned - meaning you’ll have burned half as many calories as you think - and overstated step count by more than 30%. 

Only logged-in Which? members can view our recommendations in the table below. If you’re not yet a member, you can get instant access by joining Which?.

Best Fitbit fitness trackers


This device tracks tracks distance,calories burned and heart-rate accurately much of the time. Its step-count tracking isn't quite so accurate, though.


This tracker strikes a decent balance between looks and features. It's slim and lightweight, but also has a built-in heart rate monitor. It does struggle to track calories burned, though.


The Fitbit Inspire HR is a comfortable, lightweight fitness tracker. It’s waterproof to 50m, meaning you can keep it on in the pool. It’s intuitive to use and it measures stats such as calories, distance travelled and steps taken accurately. There’s no in-built GPS, though, and you shouldn’t rely on the accuracy of its heart-rate monitor.

Fitbit fitness tracker alternatives

If a Fitbit fitness or activity tracker isn't for you, or you couldn't find what you were looking for in the table above, then don't despair. We've tested plenty of accurate and comfortable devices from other brands, including fitness watches and activity trackers from Garmin,  Misfit and Samsung. 

If you're interested in a Garmin wearable, then find out how they compare by reading our Fitbit fitness trackers vs Garmin fitness trackers guide. For more on what to spend and what features to look for, find out more about how to buy the best activity tracker or fitness watch.

How we test Fitbit fitness and activity trackers

Our tough tests put each fitness watch or activity tracker through its paces. We check the accuracy of step, distance, calorie and heart-rate tracking in different scenarios. This ranges from a routine of daily tasks, such as loading or unloading the dishwasher and carrying the shopping, to more strenuous activities. This means we can tell you the fitness trackers that accurately measure your steps, and those that don’t.

Our testers even don a face mask linked to a gas analysis system, so we can assess the number of calories they’re burning. And we don’t stop there. We know a tracker will be useless if it’s so uncomfortable you’re reluctant to wear it, so we assess how comfortable each one is during exercise and for daily life.

We’ve put several Fitbit trackers through their paces in our lab tests – if the product you're looking for isn't in the table above then head over to our Fitbit fitness tracker reviews.


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