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The Oura Ring 5 replaced the Oura Ring 4 in May 2026, and the headline change is size: Oura says the new ring is around 40% smaller by volume, with a thinner, lighter build. But size isn’t the only difference, and it isn’t the deciding factor for everyone. Here is what actually changed, and whether upgrading (or buying new) makes sense for you.
Quick Answer
- Buy the Oura Ring 5 if you want the smallest, lightest ring available, the newest sensor hardware, and don’t mind starting at a higher price.
- Buy the Oura Ring 4 if you want to save money, need a size outside the Ring 5’s range, or already own a Ring 4 and have an active membership, since most new software features roll out to both rings.
What Changed: Oura Ring 4 vs Oura Ring 5
| Feature | Oura Ring 4 | Oura Ring 5 |
|---|---|---|
| Thickness | 2.88mm | 2.28mm |
| Width | 7.90mm | 6.09mm |
| Weight | 3.3g to 5.2g | 2g to 2.69g |
| Available sizes | 4 to 15 | 6 to 13 |
| Battery life | About 5 to 8 days | About 6 to 9 days |
| Water resistance | Water resistant | IP68 (dust and waterproof to 100m) |
| Starting price* | ~$349 | ~$399 to $499 |
| Membership | $5.99/month or ~$70/year | Same, required for full features |
*Prices are approximate and change often. Always confirm current pricing on Oura’s website before buying.
Design and Comfort
The most noticeable change is physical. Independent reviewers who tested both rings side by side describe the size difference as immediately obvious in daily wear, not just on a spec sheet: the Ring 5 sits closer to a normal piece of jewelry than the noticeably chunkier Ring 4. Achieving that required Oura to redesign the ring’s mechanical, electrical, optical and battery architecture, not just shrink the case.
One trade-off: because the internal design changed, ring sizes do not carry over. A size 10 in the Ring 4 will not necessarily be a size 10 in the Ring 5. If you’re ordering a Ring 5, get a new Oura sizing kit rather than assuming your old size fits.
The size range also narrowed, from 4–15 on the Ring 4 down to 6–13 on the Ring 5. If you need a size outside that range, the Ring 4 remains the only option, and it’s still sold alongside the Ring 5.
Sensors and Accuracy
Oura says the Ring 5 uses recessed sensor domes with better skin contact, more powerful LEDs and more signal pathways than the Ring 4, aimed at more consistent readings across different finger types and skin tones. The company describes it as its most accurate generation yet, though independent, head-to-head accuracy testing between the two generations was still ongoing at several review outlets shortly after launch. Take «most accurate ever» claims from any manufacturer, including Oura, as a starting point for further reading rather than a settled fact.
Software Features: The Part That Isn’t Exclusive
This is the detail most buyers miss. Most of the 2026 feature set Oura announced alongside the Ring 5, including live workout tracking, expanded women’s health features and a «Find My Ring» tool, also rolled out to the Ring 4 and Ring 3 for members with an active subscription. In other words, a Ring 4 owner who pays for Oura membership gets nearly the same software experience as a new Ring 5 buyer. What stays exclusive to the Ring 5 is tied to the hardware itself: the smaller size, the marginally longer battery life, and Oura’s claimed sensor accuracy improvements.
Price
The Ring 4 starts lower, at around $349, while the Ring 5 starts around $399 and reaches roughly $499 for premium finishes. Both require the same ongoing membership to unlock full features. If budget is a bigger factor than size or the latest sensors, the Ring 4 remains a fully capable ring, not a discontinued afterthought.
Who Should Upgrade?
- Skip the upgrade if: You already own a Ring 4, your size isn’t offered on the Ring 5, or comfort with your current ring is already good. Most new features reach your ring through the app anyway.
- Upgrade or buy the Ring 5 if: Comfort and discretion are a priority, you fall within the 6–13 size range, or you’re buying a smart ring for the first time and want the newest hardware.
If you’re weighing a ring against a screenless band instead, see our Oura Ring vs Whoop comparison. Considering Samsung’s ring instead? Read our Samsung Galaxy Ring vs Oura Ring guide.
Frequently Asked Questions
Is the Oura Ring 5 worth the upgrade from the Ring 4?
Mainly if size and comfort matter to you. Most software features reach the Ring 4 too, so the core upgrade is physical: a smaller, lighter ring with a slightly longer battery life.
Does my Oura Ring 4 size match my Oura Ring 5 size?
No. The internal redesign means sizing does not carry over between generations. Order a new sizing kit before buying.
Is the Oura Ring 4 still worth buying in 2026?
Yes, especially if you want a lower starting price or need a size outside the Ring 5’s 6–13 range. It receives most of the same software updates as the Ring 5.
Do both rings need a subscription?
Yes. Both the Ring 4 and Ring 5 require an Oura membership for full access to sleep, readiness and health insights.
The Bottom Line
The Oura Ring 5 is a meaningful hardware upgrade, mainly a smaller, more comfortable ring with a marginally longer battery. It is not a software upgrade, since most new features also reach the Ring 4. Choose based on comfort, size availability and budget rather than assuming the newer model is automatically the better buy for you.
Last updated: September 2026.
This article was researched and written by our editorial team using the sources below, following the process described on our About Us page. It is not written or reviewed by a medical professional.
Sources
- Tom’s Guide — Oura Ring 5 vs Oura Ring 4: what’s changed
- Wareable — Oura Ring 5 vs Ring 4 key differences
- Android Central — Oura Ring 5 vs Oura Ring 4 comparison
Medical Disclaimer: This article is for informational purposes only and does not constitute medical advice. Oura Rings are consumer wellness devices, not medical devices, and their sleep and health features are estimation tools rather than diagnostic instruments. Always consult a qualified healthcare provider before making decisions about your health.