Fitbit Inspire 3 vs Garmin Forerunner 255
The Verdict
Fitbit Inspire 3 targets budget-conscious fitness enthusiasts seeking basic health tracking, while Garmin Forerunner 255 serves serious athletes demanding advanced running metrics and GPS navigation. Inspire 3 offers exceptional value at $99 with 10-day battery, AMOLED display, and core features like heart rate and sleep tracking, though it lacks GPS and always-on display capability. Forerunner 255 justifies its $349 price with built-in GPS, transflective MIP display with always-on functionality, extended 14-day battery in smartwatch mode, NFC payments, and comprehensive sports analytics specifically optimized for runners. Display quality differs substantially: Inspire 3 uses vibrant AMOLED but small 0.73-inch screen, while Forerunner 255 provides larger 46mm face with superior outdoor visibility. For casual fitness tracking and everyday wear, Inspire 3 delivers compelling value. Runners, triathletes, and athletes requiring GPS tracking and detailed training data should invest in Forerunner 255's specialized features.
Who Should Buy
Buy the Fitbit Inspire 3 if…
- →10-day battery life — charge once and forget for well over a week
- →Color AMOLED display is a huge upgrade over Inspire 2's grayscale
- →Ultra-lightweight at 20 g — perfect for sleep tracking
Buy the Garmin Forerunner 255 if…
- →14-day battery life means weekly charging at most
- →Multi-band GPS for exceptional outdoor tracking accuracy
- →Morning Report with daily training readiness and HRV status
Category Scores
Pros & Cons
Fitbit Inspire 3
Pros
- 10-day battery life — charge once and forget for well over a week
- Color AMOLED display is a huge upgrade over Inspire 2's grayscale
- Ultra-lightweight at 20 g — perfect for sleep tracking
- SpO2 and skin temperature sensors at just $99
- 5ATM water resistance for swimming
Cons
- No built-in GPS — relies on phone GPS for outdoor tracking
- No NFC — cannot use Fitbit Pay
- Tiny screen limits notification readability
- Best health insights locked behind Fitbit Premium subscription
- No always-on display option
Garmin Forerunner 255
Pros
- 14-day battery life means weekly charging at most
- Multi-band GPS for exceptional outdoor tracking accuracy
- Morning Report with daily training readiness and HRV status
- Race Predictor estimates finish times for 5K to marathon
- Lightweight at 49 g and comfortable for 24/7 wear
Cons
- MIP display lacks the vibrancy of AMOLED competitors
- No touchscreen on base model — button-only navigation
- No ECG or blood pressure monitoring
- Limited smart features compared to Apple Watch or Wear OS
- Third-party app ecosystem is small
Full Specifications
| Spec | Fitbit Inspire 3 | Garmin Forerunner 255 |
|---|---|---|
| Software | Fitbit OS | Garmin proprietary OS |
| Body | ||
| Weight | 20 g | 49 g |
| Case material | Plastic resin | Fiber-reinforced polymer |
| Water resistance | 5ATM | 5ATM |
| Health & Sensors | ||
| ECG | ||
| SpO₂ | ||
| Skin temperature | ||
| Heart rate | ||
| Sleep tracking | ||
| Battery | ||
| Battery life | Up to 10 days | Up to 14 days (smartwatch), 30 hrs GPS |
| Display | ||
| Size | 0.73 inches | 46mm |
| Type | AMOLED | MIP (Memory-in-Pixel) transflective |
| Always-on display | ||
| Resolution | 256 x 124 | 260 x 260 |
| Processor | ||
| Chipset | Fitbit custom processor | Garmin custom SoC |
| Connectivity | ||
| GPS | ||
| NFC | ||
| Wi-Fi | ||
| Cellular | ||
| Bluetooth | 5.0 | 5.0 |
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 Fitbit products or all Garmin products. View full details for the Fitbit Inspire 3 or the Garmin Forerunner 255.