Circular Ring 2: The First Smart Ring with Medical‑Grade ECG and AI Health Coaching — No Subscription Required
Why Smart Rings Are Gaining Momentum in 2025
The Circular Ring 2 is revolutionizing wearable health tech in 2025. As the first smart ring with a medical-grade ECG and no subscription fees, it’s setting a new standard. Wearable technology is shifting from wrists to fingers, and the smart ring market is booming. Users increasingly favor minimal, passive health tracking free from the visual clutter and distractions of smartwatches. Industry analysts forecast over 500% growth in smart‑ring shipments by 2027, with health tracking as the primary driver (Wareable, City Magazine).
Smart rings are smaller, lighter, and more discreet than wrist devices. Technically, fingers typically yield stronger and more stable pulse signals than wrists, enabling potentially more accurate readings for metrics like heart rate, blood oxygen saturation, and temperature trends.
Meet the Circular Ring 2
Medical‑Grade ECG with FDA‑Cleared AFib Detection
Launching at CES 2025, the Circular Ring 2 became the first smart ring to incorporate a medical-grade ECG sensor capable of detecting atrial fibrillation (AFib), backed by FDA clearance via Circular’s partnership with B‑Heart (TechCrunch). While rings like Oura and Samsung can monitor heart rate, none had offered onboard ECG until now.
Extensive Biometrics & Real-Time Monitoring
The Ring 2 continuously tracks over 140 biometric markers, including heart rate, heart rate variability (HRV), SpO₂, skin temperature, respiratory rate, sleep stages, stress estimation, energy levels, and menstrual cycle insights. Data is recorded as frequently as every two minutes—up to five times as often as many fitness trackers—providing a rich, responsive portrait of your physiology across day and night (hookedontech.com).
AI‑Powered Coaching, No Recurring Fees
The Ring 2’s built-in AI assistant, Kira, goes beyond dashboards and alerts. It analyzes patterns from multiple biometrics and delivers personalized, contextual guidance—whether it’s suggesting relaxation techniques after stress peaks or flagging recovery issues after workouts. Unlike subscription-based services like Fitbit Premium or Whoop, Circular does not require any monthly fees to access advanced features including ECG monitoring, AI insight delivery, or detailed analytics (Prelaunch).
Design, Battery, and User Experience
Premium Titanium Build and Digital Sizing
Circular has significantly improved over its previous model. The Ring 2 is crafted in hypoallergenic titanium, available in gold, silver, black, and rose-gold finishes. It weighs approximately 2 grams and features IP68 water resistance (suitable for showering and hand-washing, though not swimming) (Weekly Silicon Valley).
A standout innovation is the digital finger-sizing tool: users scan their finger with a smartphone camera to determine the exact ring size—eliminating the need for plastic sizing kits and reducing waste (Beebom).
Battery Life and Portable Charging Case
Battery endurance is notably improved. In standard “performance mode,” the Ring 2 delivers around 4‑6 days, while “eco mode” can extend battery life up to 8 days (Weekly Silicon Valley). It also supports wireless charging via a compact dock, enabling up to a month of use when paired with the charging case—ideal for travel or users who dislike daily charging routines (Tech Advisor, Weekly Silicon Valley).
How It Compares to Competitors
| Device | ECG with FDA AFib Detection | Subscription Fee | Battery Life | Design/Form Factor |
|---|---|---|---|---|
| Circular Ring 2 | ✅ Medical-grade ECG | ❌ None | ~4–6 days (perf), up to 8 days (eco) | Titanium smart ring, digital sizing |
| Oura Ring 4 | ❌ ECG not available | 💲 ~$5.99/mo | ~7–8 days | Streamlined, premium ring |
| Samsung Galaxy Ring | ❌ ECG not supported | ❌ None | ~7 days | Android‑exclusive, titanium ring |
| Ultrahuman Ring Air | ❌ ECG via paid add-on only | Optional | ~6 days | Focus on metabolism metrics |
| RingConn Gen 2 | ❌ No ECG | ❌ None | Up to 12 days | Budget-friendly ring, charging case |
Unlike the Oura Ring 4, which requires a $5.99 monthly subscription for advanced insights, or Whoop’s hardware‑free model that locks all functionality behind a $30/month fee, Circular freely provides ECG monitoring and Kira’s AI coaching out-of-the-box (Wareable, Prelaunch, Weekly Silicon Valley, Tom’s Guide, Tech Advisor, Circular, hookedontech.com, TalkSport, TalkSport).
Privacy and Data Security
Circular states that the Ring 2 is GDPR-compliant, encrypting and anonymizing all health data and allowing user-controlled sharing with caregivers or health professionals via the app. It can also sync with Apple HealthKit and Google Health Connect for broader ecosystem integration (circular.xyz, Circular). However, independent privacy audits or third-party certifications have not yet been released as of mid‑2025, leaving long-term data usage policies unclear.
Final Take: A Smart Ring Worth Watching
Circular’s Ring 2 sets a new benchmark in the smart ring sector by integrating FDA-cleared ECG, extensive real-time biometrics, and AI coaching—all without recurring costs. Its premium build, innovative digital sizing, and extended battery make it a strong contender to rival the Oura Ring and Samsung Galaxy Ring.
Still, potential buyers should remain cautious. Circular’s previous generation faced accuracy, syncing, and build‑quality issues, and full third‑party reviews are only now emerging as the device begins shipping in spring to early summer 2025 via Kickstarter and retail channels (Weekly Silicon Valley, The Verge).
Overall, if you’re seeking advanced heart monitoring and holistic biometric insights in a minimalist, reliable form—without subscription commitments—the Circular Ring 2 is definitely one to consider. Just keep an eye on independent evaluations as real-world user feedback accumulates.