I walked 5,000 steps with the Garmin Instinct 3 vs Amazfit T-Rex Ultra 2

Close-up of the Garmin Instinct 3 next to the Amazfit T-Rex 2 Ultra — (Image credit: Dan Bracaglia/Tom's Guide)

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Walk test results
Winner

Garmin Instinct 3 or Amazfit T-Rex Ultra 2, which is the more accurate fitness tracker? To find out, I slapped one on either wrist and walked 5,000 steps — manually counted, of course — and compared the data from each device.

Both smartwatches are aimed at outdoor adventurers, with rugged build qualities, onboard GPS, and no shortage of tracking modes. While the Instinct 3 debuted in January 2025, it remains one of the best Garmin watches in 2026, particularly for battery life, with a starting price of $399 via Best Buy for the solar edition and $449 for the AMOLED version.

The Amazfit T-Rex Ultra 2, meanwhile, debuted in February 2026 as Amazfit’s most premium model in a lineup of otherwise affordable smartwatches; it starts at $549 via Amazfit directly.

Garmin Instinct 3 close-up in teal on a user's wrist — (Image credit: Dan Bracaglia/Tom's Guide)

I walked 5,000 steps with the Amazfit T-Rex Ultra 2 on my left wrist and the Garmin Instinct 3 on my right wrist. Beyond my manual count, I ran Strava — my go-to app for walk/hike tracking — on my iPhone 16 Plus as a control for other metrics like distance, climb, and pace.

Find the results of my walk test between the Garmin Instinct 3 and Amazfit T-Rex 2 Ultra 2 below.

Garmin Instinct 3 vs Amazfit T-Rex Ultra 2: Walk test results

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Garmin Instinct 3 vs Amazfit T-Rex Ultra 2: results
Header Cell - Column 0	Garmin Instinct 3	Amazfit T-Rex Ultra 2	Control
Step count	5,004 steps	5,005 steps	5,000 steps (manual count)
Distance	2.72 miles	2.67 miles	2.71 miles (Strava)
Elevation gain	375 feet	435 feet	374 feet (Strava)
Average moving pace	16 mins 23 secs per mile	17 mins 19 secs per mile	16 mins 30 secs per mile (Strava)
Average heart rate	124 bpm	114 bpm	n/a
Max heart rate	150 bpm	142 bpm	n/a
Total calories burned	314 calories	345 calories	n/a
Device battery usage	4%	2%	n/a

With just a single step separating the step count totals between the Instinct 3 and T-Rex Ultra 2, and with both devices within five steps of my actual count, I'm thoroughly impressed by these results.

Strava, for what it's worth, measured my total at 4,982 steps over the course of my roughly 45-minute walk.

Distance data is similar enough across the board, with Garmin's results ever-so-slightly more in line with the control (Strava). Garmin's elevation gain data — Seattle is a darn hilly city, and this particular walk had plenty of climb — is also nearly identical to the control. The Amazfit, meanwhile, seemingly overcounted my climb efforts by as much as 60 feet, which is a tad concerning.

Close-up of the Amazfit T-Rex 2 Ultra smartwatch — (Image credit: Dan Bracaglia/Tom's Guide)

Strava and Garmin calculated roughly the same average moving pace for my walk, while Amazfit reported a slower overall average. It's worth noting that the T-Rex Ultra 2 provides just one average pace stat, and we don't know whether it reflects a moving pace or an elapsed one (though my money is on the latter).

Meanwhile, Garmin noted a higher average and maximum heart rate than Amazfit, but fewer calories burned, which is interesting. Lastly, and much to my surprise, the Garmin Instinct 3 (a class-leader in longevity) consumed twice as much battery power as the T-Rex Ultra 2.

Garmin Instinct 3 vs Amazfit T-Rex 2 Ultra: And the winner is...

Close up of Garmin Instinct 3 GPS smartwatch in Neotropic/Twilight with a grey and orange case and sea foam green strap — (Image credit: Dan Bracaglia/Tom's Guide)

By a margin of one single step — the closest ever — the Garmin Instinct 3 officially wins this head-to-head fitness tracking accuracy showdown against the Amazfit T-Rex Ultra 2. That said, I'm ultimately splitting hairs here, and both devices performed exceptionally well across the board, except for Amazfit's inflated climb data.

Was that an anomaly or a sign of a faulty barometric altimeter? I intend to find out through more comparative testing. Stay tuned for those results and a full review of the Amazfit T-Rex Ultra 2.

In the meantime, which smartwatch models should I test head-to-head next? Let me know in the comments below.

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Dan Bracaglia is the Tom’s Guide editorial lead for all things smartwatches, fitness trackers and outdoor gear. With 15 years of experience as a consumer technology journalist testing everything from Oura Rings to instant cameras, Dan is deeply passionate about helping readers save money and make informed purchasing decisions. In the past year alone, Dan has assessed major product releases from the likes of Apple, Garmin, Google, Samsung, Polar and many others.

An avid outdoor adventurer, Dan is based in the U.S. Pacific Northwest where he takes advantage of the beautiful surroundings every chance he gets. A lover of kayaking, hiking, swimming, biking, snowboarding and exploring, he also makes every effort to combine his day job with his passions. When not assessing the sleep tracking and heart rate accuracy of the latest tach gadgets, you can find him photographing Seattle’s vibrant underground music community.

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