On paper this looks close: the Circular Ring 2 has an on-finger ECG, AFib detection and a subscription-free AI coach — things the Oura Ring 5 doesn’t offer. In practice it isn’t close yet. Independent testing found the Circular’s marquee features didn’t reliably work, while the Oura Ring 5 delivers the most accurate, most polished ring experience — for a subscription.
VERDICT: TIE
Ambition vs execution. The Circular Ring 2 has unique hardware (ECG, AFib) and no subscription, but its software is unfinished and those features didn’t reliably work in testing. The Oura Ring 5 is less ambitious on paper but does everything well, accurately, with the best app — at $399 plus a membership. Today, buy Oura for a ring that works; consider Circular only as an early-adopter bet.
Oura’s tracking is accurate and reliable. The Circular’s headline ECG/AFib features didn’t reliably work in independent testing, and promised BP/glucose hadn’t shipped.
Oura Ring 5
Unique hardware
The Circular is the first ring with on-finger ECG and AFib detection — genuinely unique, if it matures.
Circular Ring 2
Subscription & cost
Circular: subscription-free (from $349). Oura Ring 5: $399 + ~$6/month. Circular is cheaper to own if the features work.
Circular Ring 2
Accuracy
Oura is the validated reference for sleep and HRV; the Circular’s data was uneven in testing.
Oura Ring 5
App & polish
Oura’s app is the category benchmark. The Circular’s software was the main thing reviewers criticised.
Oura Ring 5
Battery
Comparable — Circular ~6 days, Oura Ring 5 ~6–9. Neither is the differentiator here.
Tie
Choose Circular Ring 2
Choose the Circular Ring 2 only if on-ring ECG/AFib and AI coaching excite you and you accept unfinished software as an early adopter.
Choose Oura Ring 5
Choose the Oura Ring 5 if you want the most accurate, most polished ring that works reliably today, and the membership is acceptable.
The short version
Innovation vs execution. The Circular Ring 2 has unique on-ring ECG/AFib and no subscription, but unfinished software; the Oura Ring 5 is less novel but the most accurate, most polished ring — for a membership.
When the Circular Ring 2 is the right pick
You’re an early adopter excited by on-ring ECG/AFib and AI coaching, and accept that the software isn’t finished.
When the Oura Ring 5 is the right pick
You want a ring that works reliably today, with the best accuracy and app, and accept the subscription.
Buy the Oura Ring 5 if you want a ring that works reliably today — it’s the most accurate with the best app, for a subscription. The Circular Ring 2 has unique ECG/AFib hardware and no subscription, but its software is unfinished and those features didn’t reliably work in testing. It’s an early-adopter bet, not a safe pick.
Does the Circular Ring 2’s ECG actually work?
Not reliably, according to independent 2026 reviews — the ECG and AFib monitoring didn’t fully work during testing, and promised blood-pressure and glucose features hadn’t arrived. The hardware ambition is real, but the execution isn’t there yet.
Is the Circular cheaper than Oura?
To own, yes — it’s subscription-free from $349, versus Oura’s $399 plus ~$6/month. But you’re paying for potential; Oura’s features work today.