Amazfit T-Rex 3 Specifications
Complete verified specifications for the Amazfit Amazfit T-Rex 3, including our measured figures rather than manufacturer claims.
Last revised
Full specifications for the Amazfit Amazfit T-Rex 3, as measured and verified during our review rather than copied from a press release. Where our figure differs from the manufacturer's, ours is the one listed.
At a glance
- Manufacturer
- Amazfit
- Released
- 2024
- Category
- Wearables
- Price at review
- £279
- Our score
- 4 / 5
Full specifications
| Specification | Value |
|---|---|
| Display | 48mm AMOLED, 2000 nits |
| Battery | 21 days mixed use |
| GNSS | Dual-band |
| Rating | 10ATM, MIL-STD-810 |
| Weight | 68g |
How we verified these figures
Nothing on this page is copied from a press release. Each unit spends three weeks worn continuously, including overnight. Worn on the non-dominant wrist alongside a chest-strap heart rate monitor and a second reference watch, with all figures logged from the same sessions.
| What we measure | How |
|---|---|
| Heart rate accuracy | Beat-by-beat comparison against the chest strap across steady runs, intervals and weights. |
| GPS accuracy | The same 5km loop, twelve times, compared against a surveyed route. |
| Battery life | A fixed daily pattern — one hour of GPS exercise, always-on display, sleep tracking — run to empty. |
| Sleep tracking | Compared against a manual log of actual sleep and wake times over fourteen nights. |
| Durability | Worn through cooking, washing up and the gym, with no attempt to protect it. |
We deliberately do not publish step counts, which every device on the market gets close enough that the differences are noise. Wrist-based heart rate is least accurate exactly where people care most — high-intensity intervals.
How it compares in the category
A specification only means something next to the alternatives. These are the wearables we have measured under the same conditions.
| Model | Released | Price | Our score | Best for |
|---|---|---|---|---|
| Fitbit Charge 6 | 2023 | £139 | 3 / 5 | First-time trackers who want the basics done well |
| Whoop 5.0 | 2025 | £229 | 3 / 5 | Athletes training to a structured plan |
| Amazfit T-Rex 3 (this page) | 2024 | £279 | 4 / 5 | Hikers who want Garmin endurance without Garmin pricing |
| Galaxy Watch 7 | 2024 | £289 | 4 / 5 | Galaxy phone owners who want deep integration |
| Pixel Watch 3 | 2024 | £349 | 4 / 5 | Android users who want a watch that does not look like a fitness tracker |
| Oura Ring 4 | 2024 | £349 | 4 / 5 | People who care about sleep specifically rather than workouts |
What the spec sheet leaves out
- Sustained performance — the display figure above is a capability, not a promise about what happens after twenty minutes
- How it behaves when warm, which is where most of the difference between similarly specified wearables actually lives
- Software support length, which decides how long this stays usable and appears on no specification sheet we have seen
- The thing we actually noticed most: twenty-one days measured, which no mainstream smartwatch approaches
What the numbers mean in use
Specifications describe capability, not experience. In practice the detail that mattered most was this: twenty-one days measured, which no mainstream smartwatch approaches. That is the sort of thing a table cannot capture.
Strengths on paper and in practice
- Three weeks of battery for a quarter of the Garmin price
- Genuinely rugged to military spec
- Dual-band GPS at this price
Known limitations
- The app ecosystem is thin
- Training analysis is basic next to Garmin
- Bulky at 68g
Who this suits
This hardware is a good fit for hikers who want Garmin endurance without Garmin pricing.
Behind this page
This reference page is written from the same testing notes as the reviews it supports, and it is revised whenever the hardware or the software underneath it changes. Where a figure appears here it has been measured rather than quoted from a specification sheet.
If something on this page no longer matches what you are seeing, it is out of date rather than disputed — tell us and it gets checked again.
Related reading
The reviews this page supports go into the measurements behind these figures, and the knowledge base collects every reference page we keep.
Elsewhere in specifications: Apple Studio Display Specifications, Apple Watch Series 11 Specifications and Aqara Hub M3 Specifications.