Top fitness trackers for 2020
By Christina Woodger
Fitness trackers can specialise in a variety of activities – from outdoor pursuits to swimming, but choose one that's right for your needs to get the best results.
Whether you’re looking for a simple activity tracker for monitoring steps, calories and distance travelled, or you want one with more advanced features for running or swimming – fitness and activity trackers can cover the lot.
In this guide we pick out some of the best wearables for a variety of activities, based on how they've fared in our tough test labs.
- Best overall fitness trackers
- Best fitness trackers for steps
- Best fitness trackers with heart-rate monitors
- Best GPS-enabled fitness trackers for running
- Best waterproof fitness trackers for swimming
- Fitness trackers to avoid
- How we test fitness trackers
The trackers below are great all-rounders. They should be able to handle a wide range of sports and activities, and tracked steps and distance with little error, as well as being comfortable and durable.
Best fitness trackers
This slimline wrist fitness tracker is a proven Which? Best Buy. It tracks steps, distance and calories and uses SmartTrack to automatically recognise how you're moving around. The tracker is waterproof to 50m and has a built-in heart monitor. GPS isn't included, so you'll need to use your smartphone to track running routes.
This fitness tracker monitors steps, sleep patterns, heart rate and calories. Built-in GPS means you can track where you exercise, while a waterproof design makes it suitable for swimming in fresh water up to a depth of 50 metres. Once the device is synced with your smartphone, you'll get on-screen notifications for text messages, social media updates and emails. An impressive tracker with a good range of fitness features.
Every fitness or activity tracker will capture your steps. It's a useful metric for those wanting to keep an eye on their daily activity levels. But not all of them are equal when it comes to the accuracy of their tracking or the motivational tools they use to get you moving more.
We’ve found several fitness and activity trackers that overstated or understated steps taken by more than 30% during everyday tasks, clocking up steps when our test participants were simply flipping the pages of a magazine. But it’s not all bad news, as we’ve also found lots of trackers that are strides ahead when it comes to accuracy – including the devices below.
Best fitness watches and activity trackers for step tracking
How we test for accurate step tracking
A pedometer is the most basic sensor, and it's one you’ll find in every fitness watch or activity tracker for counting your steps.
To check the accuracy of step tracking, our test participants walk on a calibrated treadmill at 4.8km/hour for 10min and run at 9-10km/hour for 10min. They go through a series of daily tasks, including carrying shopping while walking up steps, sweeping the floor, loading and unloading the dishwasher, and reading a magazine.
We’ve tested step tracking devices that range in price from less than £20 right up to nearly £500. But, price has no correlation with the accuracy of tracking. In fact, we’ve found a £20 tracker that counted steps completely accurately, while some pricier devices struggled.
For more on accuracy, check out our guide to the most accurate fitness trackers.
A built-in heart-rate monitor is a useful feature and, if accurate, can help you track your active heart-rate zone (particularly useful if you’re looking to burn fat), and measure improvements in training. We’ve tested fitness watches and activity trackers with heart-rate monitors from brands including Fitbit, Garmin, Polar and Samsung, among others, but some devices have been beaten by our tough tests. In fact one device understated heart rate by nearly 60%.
Best fitness watches and activity trackers with heart-rate monitors
How do we test heart-rate tracking accuracy?
Our test participants go through a series of tasks while wearing a ‘telemetry monitor’ chest strap, which measures the electrical signals from their heart. They walk on a calibrated treadmill at 4.8km/hour for 10min and run at 9-10km/hour for 10 min and go through a routine of daily tasks, including loading and unloading a dishwasher, carrying the shopping and sitting reading a magazine.
We compare the heart-rate readings from the telemetry monitor with the fitness watch or activity tracker, which allows us to calculate how accurate the device is. We know consistency is just as important as accuracy, particularly when using changes in heart rate to monitor improvements in fitness over time. So we repeat our walking test to see if the trackers consistently overstate, understate or hit the accuracy mark.
If you want to leave your smartphone at home while still tracking your distance and route using your wearable device, built-in GPS is the extra feature to look for. Wearables with built-in GPS used to be at the pricier end of the spectrum, but we’ve tested several devices with this feature for under £100 – including one of the models in the table below.
Best fitness watches and activity trackers with built-in GPS
How we test for GPS accuracy on fitness trackers
All fitness and activity trackers with built-in GPS are tested for accuracy on a 1km route. The route includes dense trees and an underpass to add the challenge of potential loss of GPS signal. We even add a hill climb and compare the elevation data to Ordnance Survey topographical data to get an idea of the accuracy of the distance calculator.
Fitness watches with advanced running capabilities are put to the test on a longer, 5km, run too.
Not all fitness trackers can be used in the water. And those advertised as being pool-friendly don’t always give you much data.
But others can give you a more comprehensive picture of your swimming, tracking information such as number of lengths, pace, stroke rate, distance, duration and calories burned. Some can give you a SWOLF rating (a measure of your swimming efficiency) and some can automatically detect whether you're doing front crawl, breast stroke, butterfly or another common stroke. One we tried out even detected we were at the leisure centre based on GPS and asked if we wanted to begin a pool swim.
Be aware that, if you want to use a float at any point, to force yourself to use your legs, your device probably won't log your lengths, as you're not moving your arms. Also be aware that many devices can't give you heart-rate data in swim-mode. However, some can be paired with a heart-rate monitor chest strap.
Here are the most detailed wearables for swimming we've come across.
Best activity trackers and fitness watches for swimming
Water ratings explained
Water ratings are a confusing topic, and rating codes may mean different things depending on the type of device they are referring to. In the tables below we look at the different ratings, and what each one means in terms of how you can use your fitness tracker around and in water.
There are two main ways to find out what level of water protection or resistance your fitness tracker has. The first thing to look for is the Ingress Protection (IP) rating. These are set by the International Electrotechnical Commission (IEC), and refer to the protection provided by the casing of an electrical device in fresh water.
The first digit after the IP reflects the level of protection against solids, such as dust or grit. The second represents the protection against moisture. An IP code with an X in place of either number means the device hasn't been tested for that element. For example, a fitness tracker with a rating of IPX7 has been tested for moisture protection, but not dust.
|IP code||Level of protection|
|1 - 3||Protection against light rain|
|4 - 6||Splashproof|
|7||Protected from immersion in water with a depth of up to 1 metre for up to 30 minutes|
|8||Protected from continuous immersion in water with a depth of more than 1 metre|
The second is the water-pressure rating. These are standards set by the International Organisation for Standardisation (ISO). Pressure tests are measured in atmospheres (ATMs), and replicate the level of pressure at certain depths of water.
|Water ratings||Level of protection|
|1 ATM||Resistant to pressure equivalent to a depth of 10 metres. Splashproof, but not shower or swim proof.|
|3 ATM||Resistant to pressure equivalent to a depth of 30 metres. Splashproof and shower proof, and should be fine if accidentally submersed. Not designed for swimming.|
|5 ATM||Resistant to pressure equivalent to a depth of 50 metres. Splashproof, shower proof, can be worn swimming and snorkelling in shallow water.|
|10 ATM||Resistant to pressure equivalent to a depth of 100 metres. Splashproof, shower proof, swimming and snorkelling. Not designed for deep water diving or water sports.|
|20 ATM||Resistant to pressure equivalent to a depth of 200 metres. Splashproof, shower proof, swimming and snorkelling. Surface diving and watersports, but no deep-water diving.|
Not found the perfect product for you? Browse all of our fitness tracker reviews.
There’s a great selection of wearables in the tables on this page, but our tests have also uncovered products that are inaccurate, uncomfortable to wear, and don't meet battery life claims. These devices will soon end up shoved in a drawer, so make sure you pick the best fitness tracker rather than one of the dodgy devices in the table below.
Activity trackers to avoid
Pricing, recommendations and test scores correct as of October 2019
Our tough lab tests go the extra mile, with specialist lab equipment to check the accuracy of the tracking capabilities of each device, meaning you'll be able to precisely monitor your activity and fitness. Our panel of users gets to grips with the trackers over a number of weeks, so you can be sure we have the best advice when it comes to set-up, ease of use and comfort.
We walk and run, carry shopping and load and unload a dishwasher, all while wearing a heart-rate monitor.
These are just some of the lengths we go to in order to check how accurate a fitness tracker is. Our users try out the trackers for several weeks, too, so they can rate them fairly on comfort and usability.
The best fitness trackers are accurate, comfortable and a breeze to use, but not all devices are built the same. Poor performers in our tests have failed to track activities accurately, and we’ve found models that are so uncomfortable our users wouldn’t want them even as a gift.
To find out more about our tough lab tests, head over to how we test fitness trackers.