Amazfit makes a lot of watches across several ranges, and the model names do not make band sizing obvious. The good news is that most of them use standard quick-release spring bars, so once you know your lug width the choice opens right up.
20mm or 22mm
Slimmer Amazfit models, including the GTS range and most Bip watches, generally take 20mm bands.
Larger models, including the GTR range and the T-Rex outdoor watches, generally take 22mm.
Because these are ordinary spring bars, a 20mm band made for a Samsung Galaxy Watch or a Garmin Forerunner fits an Amazfit of the same width perfectly well. You are not restricted to bands labelled for Amazfit, which matters because the Amazfit-branded aftermarket is thinner than Samsung's or Garmin's.
How to check yours
Take the current band off and measure the gap between the lugs with a ruler. You are distinguishing 20 from 22, so precision is not the issue.
Measure the gap rather than the band itself. Bands are often cut a fraction narrower than the space they sit in, which is why measuring the band gives the wrong answer about half the time.
If your watch is one of the few Amazfit models that uses its own fitting rather than standard spring bars, the product page will say so. When in doubt, check the fit list before ordering.
Choosing a material
Silicone is the default. It handles sweat, showers and swimming, wipes clean, and is comfortable enough to sleep in, which matters on watches with the battery life to be worn around the clock.
Woven nylon is lighter and more breathable, and the better choice for long runs and hot weather. It dries more slowly than silicone after a swim.
Leather dresses the watch up considerably. The GTR range in particular has a round case and traditional proportions that carry leather well. Keep it dry.
Stainless steel and magnetic mesh give the most formal finish. Mesh is the more practical metal option because the clasp adjusts to any position rather than to the nearest hole.
Matching the band to the watch
The GTR and T-Rex are large watches, and they carry substantial bands well. A wide leather strap or a link bracelet looks proportionate rather than heavy.
The GTS is square and slim, closer to an Apple Watch in proportion. Slimmer bands suit it better, and a chunky outdoor-style strap fights the case shape.
Changing an Amazfit band
Turn the watch over and find the small lever on the spring bar inside the band. Slide it toward the centre of the band and lift that end away from the case.
To fit the new one, seat one side of the spring bar in its lug hole first, then slide the lever and let the pin drop into the opposite hole. You should feel it seat. Tug each half afterwards to confirm.
No tool needed for quick-release bands. If a band has plain spring bars with no lever, you will need a spring bar tool.
Fit and heart-rate accuracy
Amazfit watches read heart rate optically from the wrist, which needs steady skin contact. The watch should sit snug about a finger's width above the wrist bone.
Too loose and the sensor reads motion rather than pulse, which shows as a heart rate that lags behind your effort or spikes during intervals. Too tight restricts blood flow and skews it the other way.
On the larger GTR and T-Rex models this matters more, because the extra weight gives the watch more momentum during movement. A slightly loose band on a small watch produces slightly noisy data; on a big one it lets the whole watch shift.
Shop Amazfit watch bands.
