Amazfit T-Rex Ultra vs Fitbit Charge 6
The Verdict
Amazfit T-Rex Ultra and Fitbit Charge 6 target different user priorities. T-Rex Ultra excels with a stunning 1.39-inch AMOLED display (454x454 resolution), exceptional 20-day battery life, robust 10 ATM water resistance suitable for free-diving, and premium stainless steel construction at 89g. Charge 6 prioritizes practicality: lighter at 37g, includes ECG and NFC for payments, integrates seamlessly with Google services, and costs $290 less. T-Rex Ultra dominates endurance athletes seeking rugged durability and extended battery performance. Charge 6 better serves fitness enthusiasts wanting daily convenience, mobile payments, and smartphone-like features in a lightweight package. Choose T-Rex Ultra for adventure sports and minimal charging; choose Charge 6 for everyday fitness tracking and smart features on a budget.
Who Should Buy
Buy the Amazfit T-Rex Ultra if…
- →Excellent 20-day battery life with always-on display
- →Dual-band six-satellite GPS for high accuracy
- →Rugged design with 15 military-grade certifications
Buy the Fitbit Charge 6 if…
- →ECG and built-in GPS on a fitness band at $159 is remarkable value
- →7-day battery life means weekly charging at most
- →Google Maps, YouTube Music, and Google Wallet integration
Category Scores
Pros & Cons
Amazfit T-Rex Ultra
Pros
- Excellent 20-day battery life with always-on display
- Dual-band six-satellite GPS for high accuracy
- Rugged design with 15 military-grade certifications
- Free-diving rated to 45 meters
- Offline maps with route import support
Cons
- No ECG, skin temperature, or NFC payments
- No Wi-Fi or cellular connectivity
- Zepp OS app ecosystem is limited
- Heavier than most smartwatches at 89g
- No third-party app store
Fitbit Charge 6
Pros
- ECG and built-in GPS on a fitness band at $159 is remarkable value
- 7-day battery life means weekly charging at most
- Google Maps, YouTube Music, and Google Wallet integration
- Physical side button returns — much better than Charge 5's touch sensor
- Slim, lightweight band form factor for 24/7 comfort
Cons
- Small screen limits app usability and readability
- Many features require Fitbit Premium subscription
- No voice assistant or microphone on the band
- Limited third-party app support compared to full smartwatches
Full Specifications
| Spec | Amazfit T-Rex Ultra | Fitbit Charge 6 |
|---|---|---|
| Software | Zepp OS 2.0 | Fitbit OS (Google integration) |
| Body | ||
| Weight | 89 g | 37 g |
| Case material | Stainless steel bezel, fiber-reinforced polymer case | Aluminum |
| Water resistance | 10 ATM, ISO 22810 certified for free-diving to 45m | 5ATM |
| Health & Sensors | ||
| ECG | ||
| SpO₂ | ||
| Skin temperature | ||
| Heart rate | ||
| Sleep tracking | ||
| Battery | ||
| Battery life | Up to 20 days typical use, 80 hours GPS | Up to 7 days |
| Display | ||
| Size | 1.39 inch | 1.04 inches |
| Type | AMOLED | AMOLED |
| Always-on display | ||
| Resolution | 454 x 454 | 234 x 156 |
| Connectivity | ||
| GPS | ||
| NFC | ||
| Wi-Fi | ||
| Cellular | ||
| Bluetooth | 5.0 | 5.0 |
| Processor | ||
| Chipset | — | Fitbit custom processor |
Related Comparisons
This comparison is based on verified manufacturer specifications covering display, performance, camera, battery, and build quality. Scores are generated by analyzing specs across weighted categories on a 10-point scale. Learn more about our methodology.
Explore more in smartwatches, see all Amazfit products or all Fitbit products. View full details for the Amazfit T-Rex Ultra or the Fitbit Charge 6.