Comparison · 2 picks
Circular Ring 2 vs Oura Ring 5: 2026 UK Comparison
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These two rings pull in opposite directions. The Circular Ring 2 is the more ambitious piece of hardware, with sensors no rival ring offers and no mandatory subscription, while the Oura Ring 5 is the most polished and dependable ring on the market, behind a monthly fee. It is reach versus refinement.
At a glance
All 2 options side by side.
 |  | |
|---|---|---|
| Price | £399 | £280 |
| Best for | The pick for the most reliable, polished experience and the best sleep insights, if you accept the ongoing membership fee. | The pick for sensor enthusiasts who want ECG and no mandatory subscription, and can tolerate a less polished, still-maturing app. |
| Review | Read review → | Read review → |
| Buy |
The picks in detail
Oura Ring 5
Bottom line. The pick for the most reliable, polished experience and the best sleep insights, if you accept the ongoing membership fee.
Pros
- Dramatically smaller and lighter than the Ring 4 (about 40% smaller, 2-2.69g)
- Longer 6-9 day battery, up from 5-8 days
- New Blood Pressure Signals and Nighttime Breathing metrics on top of Oura's class-leading sleep tracking
- Optional charging case holds around a month of power for travel
Cons
- Oura Membership at £5.99/month (or £69.99/year) is still required for the full feature set
- £399 entry price rises to £499 for premium finishes
- Blood Pressure Signals show cardiovascular patterns, not a clinical blood-pressure reading
- No screen and a fixed size - you commit to one finger and need a sizing kit first
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Circular Ring 2
Bottom line. The pick for sensor enthusiasts who want ECG and no mandatory subscription, and can tolerate a less polished, still-maturing app.
Pros
- On-device ECG with AFib detection - rare at this price
- No mandatory subscription; all features included
- Lightweight, well-built design with a charging case
- Solid 6-8 day battery life
Cons
- Companion app is cluttered, buggy and slow to sync
- Kira+ AI health coach feels clunky and half-finished
- Promised blood-pressure and glucose trend features still unavailable
- Sleep tracking struggles with fragmented sleep
How do they differ on subscription and cost?
The Oura Ring 5 costs around £399 and keeps most of its value behind the Oura Membership at roughly £5.99 a month, bringing the three-year cost to about £615. The Circular Ring 2 starts at around £280 and has no mandatory subscription, though Circular plans to sell some future features through a virtual coin currency. For core use, the Circular is far cheaper to own over time.
If avoiding a recurring fee is a priority, the Circular has the structural advantage. Our subscription cost comparison covers how the Oura membership adds up.
Which has the more advanced sensors?
The Circular Ring 2, on paper. It is notable for including an ECG sensor, which is rare in a smart ring, and Circular has signalled blood pressure and glucose trend features on its roadmap. Alongside that it tracks sleep stages, breathing, blood oxygen, reproductive health and stress. The Oura Ring 5 sticks to a more conventional sensor set but applies it with the most refined algorithms in the category.
The catch is that ambitious sensors only matter if the software delivers reliable, well-presented data, and that is where the two rings separate.
Which app and experience is more reliable?
Oura, comfortably. Its app is the most mature in the category, with dependable syncing and a polished insight layer. Independent reviews of the Circular Ring 2 have praised the hardware but criticised the app for unreliable syncing and unfinished features. So while the Circular reaches further on sensors, the Oura is the more trustworthy day-to-day tool.
If you value a ring that simply works without fuss, that reliability gap is the most important factor in this matchup.
What about fit, battery and design?
Both are light, titanium rings with multi-day battery life, so neither demands nightly charging. The Circular Ring 2 is very light at around two grams and lasts roughly six days in testing. The Oura Ring 5 is around 40% slimmer than the previous generation, making it one of the most discreet rings available. Both are comfortable for all-day and overnight wear.
Which should you actually buy?
Buy the Oura Ring 5 if you want the most reliable, best-interpreted health data and you accept the membership. Buy the Circular Ring 2 if you are excited by ECG and an expanding sensor roadmap, you want to avoid a mandatory fee, and you can live with a less finished app. For most buyers seeking a dependable daily ring, Oura is the safer choice; for early adopters chasing features, Circular is the more interesting bet.
For the wider market, see our best smart rings of 2026 roundup.