Bottom line: The Oura Ring 5 is genuinely, dramatically smaller than the Ring 4, and that is close to the entire upgrade. The new software features arriving alongside it are not exclusive to the new hardware, so existing owners get them anyway. If you are buying your first Oura, get the Ring 5. If you already wear a Ring 4, the honest answer is that $399 buys you a thinner ring and not much else.
Check Oura Ring 5 Price → Check Oura Ring 4 Price →
Prices and specifications below were checked against Oura’s Amazon listings and DC Rainmaker’s independent review in July 2026. Both rings require a membership, which we cover further down because it changes the real cost considerably.
What Actually Changed
Oura reduced physical dimensions substantially, and the numbers are worth seeing side by side rather than described as sleeker.
| Oura Ring 5 | Oura Ring 4 | |
|---|---|---|
| Width | 6.1mm | 7.9mm |
| Thickness | 2.28mm | 2.8mm |
| Weight | 2g | 3.3 to 5.2g |
| Battery (stated) | 6 to 9 days | 5 to 8 days |
| Size range | 6 to 13 | 4 to 15 |
| Sensor light paths | 12 | 18 |
| Starting price | $399 | $349 |
Those dimension figures come from DC Rainmaker’s teardown of the differences, and he notes he bought the ring himself and pays for his own subscription. The weight change is the one people feel: dropping to 2 grams from as much as 5.2 grams is not a marginal difference on a device you wear while sleeping.
The Sizing Trap Nobody Puts in the Headline
Two separate problems here, and both hit existing owners hardest.
First, Oura’s own listing states that the Ring 5 uses sizing different from standard jewelry rings and different from other Oura generations. Your Ring 4 size does not automatically carry across. You need a new sizing kit, which means the upgrade involves a waiting step before you can even order.
Second, and more seriously: the size range shrank. The Ring 4 was available in sizes 4 through 15. The Ring 5 runs 6 through 13. If you wear a size 4, 5, 14 or 15, the newer ring is not available to you at all. That is a genuine discontinuation for people at both ends of the range, and it is buried in spec sheets rather than announced.
If you are in that group, the Ring 4 is not a compromise, it is your only Oura option, and it is $50 cheaper. Worth buying before stock of the older generation thins out.
The Part That Should Stop Most Upgrades
Here is the finding that matters most and gets the least attention. The new software features launching with the Ring 5 are, per DC Rainmaker’s review, available to recent Oura ring owners generally rather than being exclusive to the new hardware.
That reframes the whole decision. If you own a Ring 4, you are not choosing between old features and new features. You are choosing whether a thinner, lighter ring is worth $399 plus the sizing kit plus your ongoing membership. For some people who find the Ring 4 bulky, that is a fair trade. For most, it is an expensive way to lose a millimetre and a half.
This is the same pattern we found comparing what wearables actually cost over three years: the recurring fee funds ongoing software development, which is genuinely good for you, and it also means new capability often arrives without new hardware.
Sensors: Fewer Paths, Brighter Lights
The sensor change is more interesting than the marketing suggests. Oura went from 18 light paths down to 12, and compensated by increasing light brightness roughly fourfold. The company reports that this produced about a 12 percent improvement in nighttime HRV capture.
Treat that number as a manufacturer claim rather than an independent finding, because that is what it is. It is plausible, since brighter illumination improves signal quality through tissue, and it has not been independently validated. Our guide to what the validation research actually shows covers how much to trust wearable sensor claims generally, and the short version is that sleep versus wake detection is genuinely good while sleep staging is closer to a coin flip.
One honest limitation from the same independent review: the Ring 5 remains weak for sports tracking compared to basic wearables. Neither ring is the right tool if workout metrics are your priority. Our recovery tracker roundup covers what to buy instead.
The Cost Nobody Puts on the Box
Both rings require an Oura membership at $5.99 per month or $69.99 per year. That is unchanged between generations, and the Ring 5 includes the first month.
Run the three-year arithmetic. The Ring 5 at $399 plus two years of paid membership after the included month comes to roughly $539. The Ring 4 at $349 on the same basis lands near $489. Without the membership, both rings degrade to basic step and sleep-duration counters, which is not why anyone buys a smart ring.
A premium finish pushes it further. The Ring 5 in premium finishes runs $499, so the same three-year total approaches $639. That is Apple Watch money for a device that does one category of thing very well and most other things not at all.
How We Evaluate
We do not wear either ring and we will not imply we do. Dimensions, battery figures, size ranges, sensor path counts, and pricing come from Oura’s Amazon product listings and from DC Rainmaker’s independent in-depth review, which discloses that the unit was self-purchased and the subscription self-funded. The 12 percent nighttime HRV improvement is Oura’s own claim and is labelled as such rather than presented as verified. Membership pricing comes from Oura’s published rates. The three-year totals are straightforward arithmetic on those figures, shown so you can check them. Where we recommend one ring over the other, that is our editorial judgment and we say so.
Who Should Buy Which
Buy the Ring 5 if you are new to Oura. At $50 more you get a meaningfully smaller and lighter ring, slightly better stated battery, and the current generation with the longest support runway ahead of it. There is no good reason to start on older hardware.
Buy the Ring 4 if you wear size 4, 5, 14 or 15, because the Ring 5 does not come in your size. Also buy it if $50 matters to you and comfort is not a complaint, since the software experience is largely the same.
Keep your Ring 4 if you already own one and it fits comfortably. The features are coming to you regardless, the sizing process starts over, and a thinner ring is a comfort upgrade rather than a capability one. We said the same about the underlying value question in our Oura value breakdown.
Buy neither if sleep staging is your reason. The stage breakdown across all consumer wearables is far less reliable than the totals, which our sleep tracking guide gets into. If you want the ring for total sleep, resting heart rate trends, and readiness, that is well within what these do well.
Check Oura Ring 5 Price → Check Oura Ring 4 Price →
FAQ
Is the Oura Ring 5 worth upgrading from the Ring 4?
For most owners, no. The Ring 5 is substantially smaller and lighter, but the new software features are available to recent Oura owners rather than exclusive to the new hardware. You are paying $399 plus a new sizing kit for comfort, not capability.
Does the Oura Ring 5 use the same sizing as the Ring 4?
No. Oura states the Ring 5 uses sizing different from other Oura generations, so you need a new sizing kit. The available range also shrank from sizes 4 to 15 on the Ring 4 down to sizes 6 to 13 on the Ring 5.
How much smaller is the Oura Ring 5?
Width drops from 7.9mm to 6.1mm, thickness from 2.8mm to 2.28mm, and weight from between 3.3 and 5.2 grams down to about 2 grams. On a ring worn overnight, the weight reduction is the change people notice most.
Do you still need a subscription with the Oura Ring 5?
Yes, at $5.99 per month or $69.99 per year, unchanged from the Ring 4. The Ring 5 includes the first month. Without membership, both rings fall back to basic step and sleep-duration tracking.
Does the Oura Ring 5 have better battery life?
Slightly, on paper. Oura states 6 to 9 days for the Ring 5 against 5 to 8 days for the Ring 4. Real-world battery on smart rings tends to decline with age, so comparisons between a new and a well-worn ring can overstate the gap.