We set up each fitness tracker on Android, iOS and Windows where available and score how easy they are to set up and wear, and how well they track information via the band and via the related app.

We use a panel of six people (3 men and 3 women) and ge them to try on each fitness tracker. They rate how easy it is to put on and take off the band, how easy it is to adjust to get the best fit, and how comfortable the band is to use and wear daily. The scores are then averaged.

We measure how accurately each fitness tracker measures steps. Accuracy depends on what you put in as your height, weight and, in some cases, pace length, and the technology used by the fitness tracker.

We measures accuracy and how well each tracker responds to changes in heart rate, and how it deals with adverse conditions, such as sweat and motion.

Motivational points in your training regime, anything from walking around the block to hitting 10km in a week. Models vary between supplying preset goals and allowing you to customise your milestones.

Heart rate monitors are a useful barometer of effort for some people and can act as a way to measure your fitness regime more precisely.

While fitness tracking is the main purpose for these devices, notification of a text or phone call coming in from your smartphone can be very handy.

A sleep tracker claims to be able to measure when you are active in your sleep.

Built-in GPS. Some models also include GLONASS (the Russian version of GPS). Models that support GPS and GLONASS should deliver the fastest position identification.

Whether or not the device works via Android, the smartphone operating system. The Fitbits featured support a wide variety of Android devices, but not all of them. There's a comprehensive list of the supported phones on the company's website.

Whether or not the device works via iOS, the Apple smartphone operating system.