Oura Ring 5 vs 4: What's Actually Different, and Which to Buy

For most people, the Oura Ring 4 is the better buy right now: at £239 on Amazon UK against £399 for the Ring 5, it runs the same app, gets the same features and uses the same membership. Buy the Ring 5 if you have slim fingers or found earlier Ouras bulky, because its 40% smaller shell is the one difference you'll feel every day. If you already own a Ring 4, there's little reason to upgrade.

That's the short answer. The longer one depends on your finger size, how much a few millimetres matter to you, and whether you'd rather keep £160 for two years of membership.

Oura Ring 5 vs Ring 4 at a glance

	Oura Ring 5	Oura Ring 4
Amazon UK price	£399 (silver, size 10 listing)	£239 (gold, size 9 listing)
Width	6.09mm	7.9mm
Thickness	2.28mm	About 2.88mm
Weight	From about 2g	3.3 to 5.2g
Volume	40% less than Ring 4 (Oura's figure)	Baseline
Sizes	6 to 13	4 to 15
Battery	6 to 9 days	5 to 8 days
Charge time	About 80 minutes	20 to 80 minutes
Sensors	Two tri-LED emitters, two photodetectors	Red, green and infrared LEDs, three photodetectors
Offline data storage	Up to 3 days	Up to 7 days
Exterior	Titanium, PVD coated	Titanium, PVD or DLC coated (or zirconia ceramic)
Water resistance	100m, IP68	100m
App, features, membership	Same	Same

Prices are for the specific size and finish on each Amazon listing at the time of writing; other variants can cost more.

The differences that actually matter

Size and thickness

This is the reason the Ring 5 exists. Oura's Ring 5 spec page lists it at 6.09mm wide and 2.28mm thick, against 7.9mm and about 2.88mm for the Ring 4, and the company says that works out at 40% less volume. The width drop is the bigger change you'll notice. A narrower band sits more easily next to a wedding ring, catches less on pockets and gloves, and looks more like jewellery on a small hand.

On an average or large finger the gap is less obvious. Plenty of Ring 4 owners stop noticing the ring within a week, and a smaller shell won't change your data.

Size range

This one gets missed. The Ring 5 comes in sizes 6 to 13, while the Ring 4 runs from 4 to 15. If you need a 4, 5, 14 or 15, the Ring 4 is your only current Oura, and the choice is made for you. Oura also says Ring 5 sizing is slightly different, so use the right sizing kit for the ring you're buying: white Ring 4 sizers for the 4, the Ring 5 kit for the 5.

Sensors and accuracy

Oura markets the Ring 5 as "rebuilt for greater accuracy" with larger, smarter sensors. On paper the layout has changed: two tri-LED emitters and two photodetectors, where the Ring 4 had three photodetectors. Oura claims the new setup is more accurate, but nobody outside Oura has published a validation of the Ring 5 yet.

The independent evidence we do have covers earlier Oura rings, and it's good. A 2025 meta-analysis of six studies and 388 participants found no statistically significant difference between Oura and polysomnography or actigraphy for total sleep time, sleep efficiency or any sleep stage. That track record is the reason both rings are worth considering. Until Ring 5 data appears, assume the two are broadly equal on sleep.

Battery and data storage

The Ring 5 rates 6 to 9 days per charge against 5 to 8 for the Ring 4. That's one extra day at best, and both need charging about once a week. There's a trade-off going the other way, though: the Ring 5 stores up to three days of data offline, while the Ring 4 holds up to seven. If you go on long trips without your phone, the older ring is more forgiving.

Scratch resistance and finish

Both standard rings are titanium. Oura says every Ring 5 finish has a super-hard PVD coating, while the Ring 4 uses PVD or DLC depending on colour. If scratches worry you most, the Ring 4 Ceramic is the interesting option: a zirconia ceramic exterior Oura picked for scratch resistance and colour. It's the bulkiest current Oura at 3.51mm thick, so it's the opposite of the Ring 5's pitch.

Price

On Amazon UK at the time of writing, the Ring 4 listing we link is £239 and the Ring 5 is £399. Add the £69.99 annual membership and two years costs about £379 for the Ring 4 against about £539 for the Ring 5. Over three years it's £449 against £609.

What's identical

More than you might expect. Oura says software features are the same on both rings, so you get the same Sleep, Readiness and Activity scores, the same cycle and temperature insights, Oura Advisor and the same app integrations. Both are waterproof to 100m, and neither has GPS or a screen.

The membership is the same too: £5.99 a month or £69.99 a year in the UK, with the first month included for new members, and your membership carries over if you switch rings. Without it, Oura says the ring and app still work but the insights you see are much more limited. That bill applies equally whichever ring you choose.

Check Oura Ring 4 prices and sizes on Amazon£239

Who should buy which

Buy the Oura Ring 4 if you have average or larger fingers, you need a size outside 6 to 13, or you'd rather keep £160 towards the membership. It's also the one to get if you want the Ceramic finish or the longer offline storage. Our Oura Ring 4 review goes through it in full.

Buy the Oura Ring 5 if you have slim fingers, wear it alongside other rings, or tried an earlier Oura and found it too chunky. The extra day of battery is a small bonus. Our Oura Ring 5 review covers the details.

Keep your Ring 4 if you already own one and it's comfortable. You'd be paying £399 mainly for a smaller shell, since your data and features stay the same.

Check Oura Ring 5 prices and sizes on Amazon£399

If neither feels right, a few alternatives are worth a look. WHOOP suits people who want training load as well as recovery, and our WHOOP vs Oura comparison explains when a strap beats a ring. If the membership is the sticking point, the Ultrahuman Ring Air has no subscription at all, though the evidence behind it is thinner. You'll find more sleep and recovery kit in our recovery section.

Recommended reads

• Oura Ring 5 review
• Oura Ring 4 review
• WHOOP vs Oura
• Ultrahuman Ring Air review
• Sleep and muscle recovery