Circular Ring 2 Review: Brilliant, When It Works
Published: July 8, 2026
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Editor's Note: Reviewed over three weeks; ECG reliability issues were reproducible across two firmware builds.
The Circular Ring 2 does something no other smart ring can: take a 40-second ECG and an FDA-cleared AFib check straight from your finger, no subscription, no chest strap. When it works it's the most impressive thing in this roundup. The problem is a two-letter word, "when," because the software is where this ambitious ring keeps tripping over its own feet.
Is the on-demand ECG worth it?
The idea is fantastic. Electrodes on the outer band let you press and hold for a 40-second reading, results in the app, exportable as a PDF you could hand a doctor. No other ring in 2026 attempts this. On the readings that completed, it felt genuinely useful: a heart-rhythm snapshot you carry everywhere. The keyword, again, is "completed."
What's wrong with the software?
Enough that I can't ignore it. The ECG froze on a loading screen more than once across three weeks, the app crashed on sync, and features that are "coming soon" have been coming for a while. Battery also sags to four or five days in the performance mode you'll want for ECG. There's a great ring in here. It's buried under firmware that needed another six months in the oven.
Specs, Pros & the Bottom Line
Circular Ring 2
The only smart ring with on-demand ECG
- Our Rating: 3.8 / 5.0
- Price: from $349
- Battery (tested): 4–5 days
- Weight: ~4 g
- Subscription: None
- Water resistance: 50 m
- Standout: On-demand ECG + AFib
- Sizes: 6–14
Pros
- Take a 40-second ECG from your finger anytime; nothing else does this
- FDA-cleared AFib detection with no subscription
- Tracks 140+ biosignals if you like a deep dashboard
Cons
- The app is genuinely buggy; ECG froze on a loading screen repeatedly in testing
- Water resistance is only 50 m
- Battery drops to 4–5 days in performance mode
I wanted to love this one, and the app wouldn't let me. The headline is real and unmatched: a 40-second ECG and FDA-cleared AFib check taken straight from your finger, no subscription, no extra hardware. When it works, it's the most genuinely medical thing a ring can do in 2026. The problem is the "when." ECG readings stalled on a loading screen more than once during three weeks of wear, and the app crashed enough that I stopped trusting it for anything time-sensitive. Buy it only if on-demand ECG is the whole reason you're shopping and you can tolerate rough software. If you want reliability over the party trick, RingConn Gen 2 is the safer money.
What to buy instead
If reliability matters more than the party trick (and for most people it should), the RingConn Gen 2 is steadier, cheaper, and lasts far longer. Want serious heart tracking that just works? A wrist wearable still beats every ring at ECG today. Buy the Circular only if on-demand ECG on your finger is the entire reason you're shopping.
The verdict
The Circular Ring 2 is the most ambitious ring of 2026 and the hardest to recommend. The hardware reaches for something real; the software isn't ready to catch it. Early adopters who love the bleeding edge will find it thrilling. Everyone else should wait for the app to grow up, or buy a ring that already has.