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.
You may like
I walked 5,000 steps with the Garmin Instinct 3 vs Amazfit T-Rex Ultra 2
(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
Swipe to scroll horizontallyGarmin Instinct 3 vs Amazfit T-Rex Ultra 2: resultsHeader 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.
(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).
You may like
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…
(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.
More from Tom’s Guide
Follow Tom’s Guide on Google News and add us as a preferred source to get our up-to-date news, analysis, and reviews in your feeds.
