What actually changed in Ring 4
Oura didn't rebuild the Ring 4 from scratch — they refined what was already the best smart ring on the market. The changes are meaningful but evolutionary, not revolutionary.
| Oura Ring 4 | Oura Ring 3 | |
|---|---|---|
| Sensors | 18 signal pathways | 8 signal pathways |
| Battery life | Up to 8 days | Up to 7 days |
| HRV accuracy | Improved | Very good |
| Temperature | More precise | Good |
| Design | Flat inner surface | Slightly rounded |
| Charging | Magnetic | Cradle |
| Subscription | $6/month | $6/month |
| Starting price | $349 | Discontinued |
The sensor upgrade: does it matter in practice?
The jump from 8 to 18 LED signal pathways is Oura's headline claim. In practice, this means the Ring 4 is better at maintaining signal quality when the ring shifts position on your finger during sleep — the sensor array is wide enough that even if the ring rotates slightly, enough sensors stay aligned to keep the data clean.
When I switched, I noticed my HRV readings became more consistent night to night. There were fewer "anomalous" low nights that didn't correlate with how I felt. Whether that's the sensors or just better baseline calibration from years of use, I can't say with certainty — but the data quality felt meaningfully better.
Battery life: a real improvement but not dramatic
One extra day of battery sounds minor, but it matters when you're charging while getting ready in the morning. The Ring 4 gives you more buffer — if you forget to charge one night, you're not immediately out of data the next day. In practice I charge every 5-6 days and never worry about it.
The flat inner surface: surprisingly important
This sounds like a trivial design change, but anyone who wore the Ring 3 long-term knows the rounded inner surface could feel slightly uncomfortable after weeks of continuous wear. The Ring 4's flat inner surface sits more naturally and causes less of that subtle pressure awareness over time. Not a dealbreaker either way, but I notice it.
What stayed exactly the same
The fundamentals: sleep tracking quality, temperature monitoring, Readiness Score logic, app experience, and subscription model. If you loved your Ring 3 data, you'll love the Ring 4 data. If you found the Ring 3 app confusing, the Ring 4 doesn't fix that.
The subscription is still $6/month either way. And both rings require it for the full experience.
The honest upgrade advice
If your Ring 3 is working fine: keep using it. The data you get today is still excellent. Upgrade when it starts having battery issues or sensor problems — they do degrade over time with daily charging cycles.
If you're buying for the first time: Ring 4 is the only current option anyway, and it's genuinely the best smart ring available.
If Oura offers a trade-in deal (they occasionally do): worth doing. The sensor improvement is real enough to justify the cost if the out-of-pocket is manageable.
Frequently asked questions
Is the Oura Ring 3 still being sold?
No. Oura discontinued the Ring 3 when the Ring 4 launched. You can still find it on second-hand markets, but it's no longer sold new through official channels. If you're buying new, the Ring 4 is the only option.
Does the Ring 4 charger work with the Ring 3?
No. The Ring 4 uses a new magnetic charger that is not compatible with the Ring 3 cradle charger. If you upgrade, you'll need the new charger (included in the box).
Does the Ring 4 transfer data from Ring 3?
Yes. Your historical data is stored in your Oura account, not on the device. When you switch to the Ring 4 and log into the same account, all your Ring 3 history is still there. The transition is seamless.
Is the sizing the same between Ring 3 and Ring 4?
Mostly, but not exactly. The Ring 4 has a slightly different inner profile (flatter surface). Most people use the same size, but it's worth requesting a new sizing kit if you're unsure, especially if your Ring 3 was borderline between two sizes.
How much does it cost to upgrade from Ring 3 to Ring 4?
The Ring 4 starts at $349 for the silver finish. Oura has occasionally offered trade-in credits for Ring 3 owners — check their website for current promotions. There is no discounted upgrade path by default.