Oura Ring 5 vs Ring 4: which should you buy?

This comparison is mostly about whether a smaller ring changes how consistently you wear it. With an active membership, Oura says Ring 5 and Ring 4 receive the same software features. Ring 5 doesn’t unlock a separate set of sleep, readiness, stress or heart-health screens.

That makes comfort the headline, which isn't glamorous but is the whole game. A smarter ring in the bathroom drawer measures nothing.

The useful hardware change is physical. Ring 5 measures 6.09mm wide and 2.28mm thick; titanium Ring 4 measures 7.9mm wide and about 2.88mm thick. That makes Ring 5 roughly 23% narrower and 21% thinner by those published dimensions. Oura's larger "40% smaller" statement refers to volume, not thickness.

Oura announced Ring 5 on May 28, 2026 and began shipping it on June 4. That makes it the current generation, but recency alone isn’t a reason to replace a Ring 4 that still fits and works.

Oura Ring 5 vs Ring 4 at a glance

This table compares the standard titanium Ring 4 with Ring 5. Ring 4 Ceramic is heavier and thicker, so it shouldn’t be used to exaggerate the difference between the two titanium models.

Buy Ring 5 when comfort is the reason you stopped wearing a ring

A health wearable only collects useful longitudinal data when it stays on the body. Ring 5's best upgrade is therefore not a new score; it’s less hardware between adjacent fingers. Oura lists weights of about 2.0 to 2.69 grams for Ring 5 versus 3.3 to 5.2 grams for titanium Ring 4, depending on size.

Early independent reviews support the comfort change. TechCrunch found Ring 5 less noticeable during sleep, while WIRED described the smaller design as the generation's most meaningful improvement. That doesn’t prove every hand will prefer it. A correct 24-hour sizing test matters more than a reviewer's finger.

Oura also uses what it calls a superhard PVD finish on Ring 5 and claims better scratch resistance than Ring 4. Treat that as a manufacturer durability claim, not permission to ignore ordinary wear; Oura's warranty excludes everyday scratches and dents.

Accuracy isn’t a clear Ring 4 upgrade case

Oura's own comparison says both generations receive the same software features with membership. That removes the usual upgrade argument. A Ring 4 owner isn’t missing a separate Ring 5 readiness score, sleep dashboard or stress feature simply by keeping the older hardware.

Oura says Ring 5's redesigned optical system improves overnight HRV and workout heart-rate accuracy. Those percentages come from Oura's internal validation. Ring 5 actually uses two photodetectors versus three in Ring 4, which is a reminder that sensor count alone doesn’t establish performance. There isn’t The evidence reviewed for this guide didn’t include broad Ring 5-specific peer-reviewed validation proving a major health-accuracy leap across a representative population.

For hard intervals and serious training decisions, neither ring should replace a chest strap or another validated exercise heart rate path. Android Central found Ring 5 could read materially low during high-intensity exercise even when its resting readings aligned more closely with other wearables.

Ring 5 doesn’t produce a blood-pressure reading

Oura's Health Radar and Blood Pressure Signals can look for longer-term patterns associated with cardiovascular strain and accept a manually entered cuff reading. They don’t produce systolic or diastolic numbers, and Oura says the feature isn’t diagnostic. It’s also a supported-feature rollout for eligible Gen3-and-newer members rather than a reason to buy Ring 5 alone. See Oura's current Health Radar documentation.

Size first: Ring 4 and Ring 5 kits aren’t interchangeable

Oura sizes aren’t standard US ring sizes, there are no half sizes, and the fit changed between generations. Don’t infer a Ring 5 size from an old Ring 4 kit or from a jewelry size. Oura recommends wearing the correct generation-specific sizer for at least 24 hours because fingers change with temperature, sleep and activity.

• Use the white Ring 5 sizing kit for sizes 6-13.
• Test the index, middle and ring fingers on both hands.
• Confirm the fit overnight and during an ordinary day.
• Make sure the ring comes off without force when the finger is warm.
• Select the actual ring only after the full-day test.

The Ring 5 Amazon buttons in this guide point to one exact Silver Size 8 offer verified before publication. They aren’t a recommendation that Size 8 fits you. Confirm the selected child variation, generation, finish, condition, seller and shipper again before checkout.

Both generations also require a compatible phone path. Oura currently lists iOS 16 or later, or Android 11 or later with Google Play services, plus Bluetooth 5.0 and a supported country for membership and feature access. Check the current Oura setup requirements before treating either ring as phone-compatible.

Your old charger doesn’t carry over

Oura chargers are both generation-specific and size-specific. Ring 4 charging docks and cases work only with Ring 4; Ring 5 docks and cases work only with Ring 5. Even within the correct generation, the charger must match the physical ring size.

That adds friction to an upgrade and to a household with multiple ring sizes. Count the correct charger or case as part of the setup rather than assuming an existing accessory reduces the cost.

Battery improves slightly, but offline storage gets worse

Oura rates Ring 5 for a typical 6-9 days and Ring 4 for 5-8 days. The top number isn’t a guarantee. Ring size, settings, enabled features, battery age, activity and temperature all change the result. Independent Ring 5 reviewers generally report around a week rather than assuming nine days.

Ring 4 has a less obvious advantage: it can store up to seven days of data before syncing, while Ring 5 stores up to three. If a phone is routinely unavailable for a long backcountry trip, restricted workplace or digital break, that difference may be more useful than one extra day in the battery claim.

The built-in lithium-polymer battery isn’t user-replaceable. Battery aging can therefore become a legitimate reason to replace an otherwise functional Ring 4, but Oura's limited warranty lists batteries as consumable parts rather than ordinary covered wear.

The membership cost is the same decision on both rings

Oura membership belongs to the account, not the physical ring. Existing members keep their data and benefits when pairing Ring 5, but buying an additional ring on an existing account doesn’t create another included month. Without membership, Oura limits the app to the three daily scores, battery information, basic profile and settings, and Explore content.

As of August 1, 2026, Oura lists US membership at $5.99 per month or $69.99 per year. New members receive one included month and the selected plan then renews automatically unless canceled. Existing members don’t receive another included month simply for adding a ring. Pricing and terms can change, so confirm them on Oura's current page before checkout.

Use the current Oura membership page before buying. A useful ownership worksheet is: current ring offer + membership for the period you expect to keep it + any size-specific spare charger or case. If that recurring total is unacceptable, neither generation is the right purchase.

Verify a new authorized offer before buying an older Ring 4

A low Ring 4 price is only useful when the exact selected offer is new and authorized. Oura's US warranty covers manufacturing defects on new products for one year, but excludes ordinary wear, scratches, dents and consumable parts including the battery. Unauthorized secondhand products may lack warranty coverage and can be restricted if linked to a previously reported issue.

No verified authorized Ring 4 Amazon offer was available during the August 1, 2026 check, so this guide omits that commerce button. Don’t let a third-party or used offer silently become the basis for a comparison against a new Ring 5. Oura also warns that an unauthorized secondhand ring can be restricted when it is tied to a previously reported issue.

Who should buy neither Oura Ring?

• You want full data without an ongoing membership.
• You need a screen, notifications, maps or live workout guidance.
• You need precise high-intensity exercise heart rate.
• You expect a medical diagnosis or treatment recommendation.
• You can’t get a stable fit with the generation-specific sizing kit.

Oura explicitly says its ring isn’t a medical device and isn’t intended to diagnose, treat, cure, monitor or prevent medical conditions. A wellness trend can be useful context, but it should not change medication, nutrition or training without appropriate professional guidance.

How we reached this recommendation

We compared Oura's current Ring 5 and Ring 4 support pages, generation-specific sizing and charging documentation, membership terms, warranty boundaries and medical-device disclaimer. We separated Oura's internal accuracy claims from independent review observations and didn’t treat earlier-generation research as Ring 5-specific validation.

We also checked exact US Amazon offers for a Silver Size 8 Ring 5, Silver Size 8 Ring 4 and the Ring 5 sizing kit. Exact offers can change after publication, so a purchase button is a route to a product page—not proof that the selected condition, seller or shipper remains the same.

The verdict

New buyer: Ring 5 is the default when sizes 6-13 fit. Its narrower, thinner and lighter hardware is the clearest everyday improvement, and a ring that stays on produces the most useful continuity.

Current Ring 4 owner:keep it if it already fits comfortably, lasts through your charging routine and syncs reliably. The shared software means there’s no strong feature-only upgrade case. A thinner ring is useful; buying the same dashboard twice isn't.

Ring 4 buyer:choose it only for sizes outside Ring 5's range, Ceramic, seven-day offline storage or a materially better verified new-authorized offer. Buy neither when the membership or medical limitations conflict with the job.

FAQ

Sources

• Oura Ring 5 specifications and Ring 4 comparison
• Oura Ring 4 specifications
• Oura generation-specific sizing guide
• Oura charger compatibility
• Oura membership terms
• Oura warranty terms
• Oura medical-device boundary
• Oura Health Radar and Blood Pressure Signals
• Oura phone and setup requirements
• Oura product safety, water-use and battery details
• Oura disabled-ring policy
• Oura Ring 5 engineering claims
• TechCrunch Oura Ring 5 review
• WIRED Oura Ring 5 review
• Android Central Oura Ring 5 review