Where they actually differ
The most decisive specs, ranked by how much they matter — before the full spec table.
| Spec | Google - Fitbit Inspire 3 | Oura - Ring 4 |
|---|---|---|
| Battery life | 10 days | 8 days |
| Sport modes | 21 | 40 |
| Water resistance | 5 ATM | 10 ATM |
Between the Fitbit Inspire 3 and Ring 4, the Fitbit Inspire 3 comes out ahead in battery life, while the Ring 4 wins on sport modes / water resistance. Overall, the Fitbit Inspire 3 scores 66.4 and the Ring 4 scores 63.8 on our Mars Score.
Which should you buy?
These two are nearly even on the Mars Score (66.4 vs 63.8). The decision is not about overall quality — both clear the bar — it is about which specific trade-offs fit your use.
Pick the Fitbit Inspire 3 if you care most about battery life. The biggest gaps in its favor are battery life. The single most decisive one: Battery life — 25.00% more. 10 days vs 8 days.
Pick the Ring 4 if you care most about sport modes / water resistance. Its strongest claims are sport modes, water resistance. The single most decisive one: Sport modes — 19.00 more. 40 vs 21.
Both ship with comparable gps, spo2, so those specs do not separate the two — focus on the differences below.
Bottom line: there is no wrong answer here — match the spec advantages to how you actually use the product. The Mars Score parity says both are well-rounded; the differences are about trade-offs, not quality.
Which should you buy: Google - Fitbit Inspire 3 or Oura - Ring 4?
Google - Fitbit Inspire 3 leads the current Mars Score by 2.6 points.The more useful decision is the trade-off behind that result: compare battery life against the way you will actually use the product.
Choose Google - Fitbit Inspire 3 if…
Google - Fitbit Inspire 3 has the measurable edge on battery days.
Choose Oura - Ring 4 if…
Oura - Ring 4 has the measurable edge on sport modes, water resistance atm.
This is a structured comparison of the published catalog values. It is not a claim of identical real-world performance across every workload; use the linked spec drill-downs and methodology page to inspect the inputs.
Why Google - Fitbit Inspire 3 wins
- ▲Battery life — 25.00% more. 10 days vs 8 days.
Why Oura - Ring 4 wins
- ▲Sport modes — 19.00 more. 40 vs 21.
- ▲Water resistance — 5.00 ATM more. 10 vs 5.
Spec comparison
Fitness
| Spec | Google - Fitbit Inspire 3 | Oura - Ring 4 |
|---|---|---|
| Form factor | Band | Ringlead |
| GPS | false | false |
| Heart rate | true | true |
| SpO2 | true | true |
| Sleep tracking | true | true |
| Sport modes | 21 | 40lead |
Battery
| Spec | Google - Fitbit Inspire 3 | Oura - Ring 4 |
|---|---|---|
| Battery lifeⓘ | 10 dayslead | 8 days |
| Water resistanceⓘ | 5 ATM | 10 ATMlead |
Design
| Spec | Google - Fitbit Inspire 3 | Oura - Ring 4 |
|---|---|---|
| Display size | 0.74 "lead | 0 " |
| Weight | 21 g | 3.3 glead |