How to buy the best fitness tracker
The right activity tracker can provide you with an accurate, comprehensive and easy-to-understand view of your health, whether you’re running, cycling, swimming, monitoring your heart rate or just trying to up your step count.
But paying for features you won't use, or for a device that's not designed for your type of exercise, is a common mistake. Our guide can help you settle on the perfect wearable so you can track your fitness and activity with a device you can trust.
Video: How to buy a fitness tracker
How much do fitness trackers cost?
You can buy a tracker for less than £13, or you could pay close to £250. If you buy an ultra cheap tracker, it's likely not to be that great, so it's risky to shop at the cheap end of the market. Beyond that, though, our testing has shown there’s little correlation between price and accuracy.
It’s absolutely possible to pick up a great, affordable fitness tracker if you don’t mind missing out on some more advanced functions. For a selection of budget-friendly options that impressed in our tests, read our guide to the .
Fitness tracker features to look out for
Some fitness or activity trackers pack in a wide range of sensors to track everything from steps and heart rate to your exact location and even the intensity of sunlight, to let you know when it’s time to reach for the sunscreen. This can result in more detailed feedback but, as revealed by our tough tests, not every device is accurate.
On top of that, having too many sensors can reduce the battery life of your device or make it more complicated to use (we rate ease of use in our tests too), so it's important to get the right balance.
A pedometer is the most basic sensor, and one you’ll find in any activity tracker. This will count your steps and can often capture distance, too, based on an estimation of your stride length. We put the step counter through its paces in our tough lab test and check the accuracy.
If your wearable has built-in GPS, it can track distance more accurately – as long as the GPS works well and doesn’t drop the connection. Many fitness trackers can be paired to your mobile phone to make use of your phone’s GPS, but built-in GPS is useful if you want to jog or cycle without carrying your phone.
A heart-rate monitor is another option worth considering. This, as you might expect, will measure your heart rate throughout the day. It will report on your average heart rate, and periods of peaks and troughs – useful for tracking improvements in your fitness.
Again, accuracy is important here, and this can vary a fair bit between different makes and models. We rate this as part of our lab tests too, to find good trackers that don't miss a beat.
More accurate heart rate monitoring should also mean more accurate VO2 max estimates (estimates of your maximum rate of oxygen consumption), if your tracker offers that. VO2 max data can be useful for climbers, people preparing for a particular event and athletes.
Most trackers, including cheap ones, will now keep an eye on your sleep, including motion sensing to see whether your sleep is disturbed, and offering you an estimate of how much of your sleep has been spent in REM, light sleep and deep sleep. Some have a sleep cycle alarm, meaning your tracker will wake you up at the optimal time in your sleep cycle that’s close to your desired wakeup time. If you're interested in sleep tracking, we have a dedicated guide on .
Typically, if your fitness or activity tracker is rated for water resistance, there will be a list of obscure letters and numbers to reference how well protected it is against water. For example, an IP68 rating means that the device can be immersed in water at a depth of a metre or more, for a set period of time. An ATM rating is also important; a 1 ATM rating or higher means the device is water resistant up to 10 metres of pressure or higher. The pressure is important because, while you can take the wearable down to a certain water depth, if you sprayed the watch with a high pressure hose, it may not survive the experience.
If you already use an app on your smartphone or wearable, such as Strava or running app Map My Run, you won’t want to lose access to your data or the in-depth analysis dedicated apps can offer. Smartwatches are more likely to offer compatibility here, allowing you to pair with app services and sync the data from your wearable.
If you want to listen to music on your run without taking multiple devices out with you, look for a smartwatch that has built-in storage to store your tunes. You'll need a Bluetooth headset as well though. Music management is not a feature that's commonly found on activity trackers, so head over to our to browse all the models we've tested.
How important is fitness tracking accuracy?
If you're taking your exercise regime seriously, accuracy will be quite high on your list of priorities.
Even if you're new to exercise, and you only want to track your metrics casually, it's still important for your tracker to be able to correctly identify general trends – rather than feeding you stats at random, which will leave you groping in the dark about your progress.
We test trackers to see how accurate they are at measuring steps, distance and heart rate. And we take consistency into account as well. If a tracker is accurate on some days but not on others, you won’t know whether you’re improving.
How long do the batteries last?
Using your wearable could become irritating if you find yourself needing to charge it too frequently. Generally, activity trackers have the advantage over smartwatches here – they're simpler devices with smaller screens, so won't drain as fast.
Most activity trackers have a battery life that ranges from a couple of days to a couple of weeks. Some models use coin-cell batteries, like a watch, and these will last several months before needing replacing.
Smartwatches, on the other hand, may need charging every day under heavy use.
The best overall fitness trackers
Below we've hand-picked some fitness trackers that work as great all-rounders, with impressive accuracy and comfort, and a good range of features.
Table last updated February 2021