Check your heart rate in 40 seconds
Your heart can feel different in an instant and uncertainty can stay with you for hours. Circular Ring 2 lets you run a 40-second ECG directly from your finger, so you can check your rhythm when the moment happens, not after it has passed. You get fast, clear insight that helps you understand what is going on and decide your next step with more confidence.
Most People Miss What Their Heart Is Telling Them
Annual Checkups Aren’t Enough
A yearly visit captures one moment. Your heart rhythm can change between appointments.
Symptoms Often Come Late
By the time palpitations, fatigue, or breathlessness appear, the issue may already be developing.
Subscriptions Add Friction
Some trackers charge monthly fees to unlock key health insights—turning access into an ongoing cost.
A Smarter Way To Track ECG & AFib
Circular Ring 2 gives you a faster, simpler way to check your heart rhythm without waiting for an appointment, relying on late symptoms, or paying monthly to access key insights. With a 40-second on-demand ECG from your finger, you can check in when questions come up and keep a clearer view of your heart over time.
Check Beyond Appointments
Run an on-demand ECG anytime or anywhere.
Earlier Awareness
Check when something feels off, not only after symptoms grow.
No Monthly Fees
Your ECG insights stay accessible without extra cost.
40-Second Readings
Fast, on-demand ECG from your finger.
Ring-Form Comfort
A discreet way to wear ECG daily.
More Than ECG
13+ health features in one ring.
The Only Smart Ring With ECG & AFib Detection
See How Circular Compares
Feature
Circular Ring 2
Apple Watch 9
Samsung Watch
ECG heart rhythm check
Yes (dedicated electrode)
Yes (wrist electrode)
No
AFib detection
Yes
Yes
No
ECG Reading Time
40 seconds
30 seconds
No
Shareable PDF report
Yes
Limited
No
ECG + All Health Data in One App
Yes
Partial
No
Battery life
Up to 8 days
Up to 18 hours
Up to 7 days
Water Resistance
IP68
WR 50M
IP68
When People Use Circular Ring 2 to Track Their ECG
A Sudden Flutter During The Day
You feel an unexpected irregular beat during work or rest. Instead of ignoring it, you run a quick ECG and check your rhythm immediately.
After A Stressful Period
Long days, pressure, and fatigue build up. Your heart feels different, and you want to understand if stress is affecting your rhythm.
Following Poor Sleep
After several nights of weak sleep, your body feels off. You check your ECG to see how your heart is responding.
Post-Workout Check-In
After an intense session, your heart feels unusually strained or inconsistent. You take a reading to better understand your recovery state.
After A Previous Warning
A past alert or doctor conversation stays in your mind. You use ECG to monitor your rhythm more regularly and stay aware.
When Something Just Feels Off
There is no clear symptom, just a sense that something is not right. Instead of waiting, you check and get clarity in the moment.
Technical Specifications
Titanium body, hypoallergenic interior
2.55mm thick, 7.8mm wide, 3 grams
Sizes: US 6–14
Battery: 8 days (Power Mode), 5 days (Performance)
Charging: 30 mins via wireless charger
ECG, PPG, temp sensor, 3x accelerometer
Bluetooth Low Energy, Airplane Mode
iOS & Android compatible
GDPR & HIPAA compliant
Kira, your AI health coach
One reading is a moment. Kira watches the whole picture.
Kira, the Circular AI health coach, watches all of your health signals every day. Translaties in plain language, explains what your data actually means for your life and shares actionable insights. She does not just surface numbers. She provides context.
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From people who wear it
4.9
Came for the ECG, that was the whole plan. First week Kira hit me with: your sleep is wrecking your stress recovery way more than your workouts are helping it. Bro. I restructured my entire week after that one sentence. Still think about it honestly.
Martin
4.8
My mum is 68 and very particular. Anything that looks like a health device goes straight in the drawer. This didn't. She wore it, figured out the ECG herself, and showed her doctor. I couldn't believe it.
Rachel P.
4.9
First pregnancy and my body just feels different every week. Started using Circular to understand what's actually changing. The ECG, sleep, stress all together. Kira basically became my daily check in. I didn't expect to rely on it this much.
Jessica B.
More Than An ECG Tracker. 13+ Features Included
One signal tells you something. Thirteen together tell you everything.
ECG tracker on your finger is only the beginning. Circular Ring 2 brings together 13+ connected health features, including sleep, stress, HRV, activity, SpO₂, temperature, energy, cycle, and many more paired with actionable AI insights.
Kira AI Coaching
Your complex data, turned into clear tips tailored to your lifestyle.
Sleep cycles
Oxygen levels and breathing patterns tracked while you sleep.
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Woman’s health
Cycle, symptom, and hormonal tracking with high precision.
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Calories burn estimation
Energy usage based on real activity and body data.
Stress monitoring
Learn when your body is stressed and needs rest or when it is ready to perform
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HRV
Stress insights showing when your body needs rest or is ready to perform.
Questions about ECG tracking
Is Circular Ring 2 really the only smart ring with ECG?
As of 2026, yes. Circular Ring 2 is the first and only smart ring to offer on-demand ECG readings and irregular rhythm detection.
How do I take an ECG reading with the ring?
Open the Circular app and navigate to the Heart Rhythm circle. In your ring settings, confirm which hand the ring is on. Then place a finger from your opposite hand on the small sensor dot on the ring's face and hold still for 40 seconds. The app will process the waveform and display your result.
Why do I need to touch the ring with my other hand?
Opposite finger completes an electric circuit across chest (Lead I equivalent), enabling heart signal detection.
What results can the app show?
After each 40-second reading, the app classifies your rhythm as one of the following: normal sinus rhythm, possible AFib, possible tachycardia, possible bradycardia, or unclassifiable. Each reading also generates a PDF report formatted for physician review.
What should I do if a reading flags an irregular rhythm?
The recommended next step is to share the PDF report with your doctor for confirmation. The app does not diagnose conditions. It surfaces patterns that may be worth discussing with a medical professional.
How accurate are the readings?
For best accuracy, take readings while seated and at rest, in the same conditions you would be asked to maintain in a clinical setting. Movement, dry or cold fingers, post-exercise state, or a loose ring fit can reduce signal quality. If the reading is poor, the app will notify you and suggest trying again.
How often should I check my heart rhythm?
For general wellness monitoring, once or twice a month is a reasonable baseline. If you have a known history of arrhythmia, or if your doctor has recommended more frequent monitoring, daily readings are fully supported with no cooldown between sessions.
Does this feature require a subscription?
No. ECG tracking is included with the Circular Ring 2 at no additional cost. There is no monthly fee to access this feature or any other core feature.
How is this different from Apple Watch ECG?
Apple Watch also offers single-lead ECG. The key differences are form factor, battery life, and pricing model. Circular Ring 2 is a ring, which many users find more comfortable for continuous wear. It lasts 8 days on a single charge compared to Apple Watch's 18 hours. And it requires no subscription for core features, where some Apple Watch health features require an Apple subscription tier. Additionally, Circular provides a zero-distraction experience; unlike the Apple Watch, which constantly interrupts with notifications and apps, our ring works silently in the background so you can focus on your health without the screen fatigue
Is this the same as a hospital ECG?
They use the same underlying electrical measurement principle. A hospital ECG typically uses 12 leads simultaneously to build a detailed map of the heart's electrical activity and detect more advanced patterns. Circular uses a single-lead measurement, which is the same approach as most consumer ECG wearables. Single-lead readings are effective for detecting rhythm irregularities. They are not a substitute for a full clinical evaluation.
What are all the features/signals Kira can relate to ECG?
Everything in your sleep and energy and stress circles. HRV/stress, sleep/recovery, respiratory rate/SpO2, activity load, energy trends, manual notes.
Does the ring store raw ECG waveform data, or only processed results?
Raw waveform for PDF; stores processed results/trends.
Does Kira interpret ECG data directly, or is ECG handled separately from Kira? If Kira does interact with ECG, what exactly does it do?
Kira analyzes post-reading, correlates with vitals, gives summaries/pattern
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