Oura Ring 5

Why the newer ring ranks lower here

This is the clearest example on the site of our rubric doing something a normal review site would never do. The Ring 5 is probably a better device than the Ring 4 — newer sensors, a smaller body, an improved platform. It also has no published validation, and evidence is 30% of the score.

The reasoning is not stubbornness. A validation exists precisely to test a new sensor and a new algorithm; inheriting a predecessor's paper is exactly the move a validation is designed to prevent. Oura's reputation for sleep accuracy was earned by a Gen3 ring in a Brigham and Women's Hospital study, and it belongs to that ring until somebody re-runs the test.

What the Oura evidence actually says

• Sleep staging.In a study of 35 healthy adults with single-night inpatient polysomnography, the Oura Ring Gen3 achieved 76.3% four-stage agreement and 79.5% deep-sleep sensitivity — the best of three devices tested. Oura's own release rounded that four-stage figure to 79%; the paper says 76.3%, and we use the paper.
• HRV. Across 536 nights against a single-lead ECG, Oura Gen 4 recorded 5.96% mean absolute percentage error and Gen 3 recorded 7.15% — the two best results of five devices tested, ahead of Whoop 4.0, a Garmin fēnix 6 and a Polar Grit X Pro.
• The Ring 5. Nothing. Not one published measurement that we could find.

Both of those studies have limits the authors state plainly — one night, lab conditions, healthy adults without insomnia in the sleep study; 13 participants in the HRV study — and we publish those limits alongside the numbers on our sleep accuracy page.

The money

The Ring 5 costs more than the Ring 4 and carries the same mandatory membership. Oura's published pricing is $5.99 per month or $69.99 per year, with the first month free, and the company states that without a membership the ring and app still work but the insights are much more limited.

Over three years that works out to $609 for the Ring 5 against $559 for the Ring 4. You are paying more for the version with less evidence behind it, which is a strange sentence to write and an accurate one.

Who should buy it anyway

People who want the current generation and are comfortable that a newer Oura is very likely at least as good as an older one. That is a reasonable bet — it is simply a bet, and this site's job is to be clear about which of our statements are measurements and which are expectations.

If you want the measured device, buy the Ring 4. If you want to escape the membership entirely, the RingConn Gen 2 has no subscription — and no validation either, which we say just as loudly.

Sizing, and the failure mode nobody warns you about

Rings are sold per size and the listing you buy is size-specific. Fingers swell in heat and shrink in cold, and a ring that is loose reads badly for the same reason a loose watch does: optical sensing needs consistent contact with skin. Use the maker's sizing kit before ordering, and size for your normal evening state rather than a cold morning, because the measurement that matters most to you happens overnight.

The second practical point: a ring cannot record training. No GPS, no display, no pace. If you want one device for both jobs, you want a watch — and you should read what has been measured about watch sleep staging first, because it is very little.

What would change this ranking

One thing: a published validation of the Ring 5 itself. Specifically, a study against clinical polysomnography for sleep staging, or against a timestamped ECG for heart-rate variability, with limits of agreement reported rather than a correlation coefficient.

If that appears, this page will be rewritten and the ranking will move — up or down, depending on what the study says. That is the point of ranking on evidence rather than on release dates: the position is falsifiable, and we have said in advance what would falsify it.