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Latest ECG
Sinus rhythm
62bpm
ECG and AFib detection
Forty seconds at your finger, screened for atrial fibrillation, exportable as a PDF.
Circular Ring 2
The smart ring for 24/7 health tracking
$299.00
$349.00
Sale 14%
140+ biosignals across 13+ health features, from a single-lead ECG to AI coaching. A health lab on your finger, with no mandatory subscription.
Clinical-grade ECG and AFib detection — forty seconds at your finger, result in the app.
Free feature upgrade — Blood Pressure, glucose trends and more coming soon.
Kira AI health coach — your own numbers, read back in plain language.
No mandatory subscription — every core feature included with the ring.
ColorObsidian Black
Size
I know my size
Pick it below and we ship straight away.
Send me a sizing kit first
You don't need to know your size. Replica rings arrive first. +$5
We post a set of replica rings in every size. Wear the one that fits for a day, tell us which it was, and your ring follows — nothing more to pay.
Add to your order
As covered inForbesWiredTechCrunchVogue
Worldwide shipping
14-day returns
1-year warranty
24/7 support
No mandatory subscription
Every core feature is included with the ring — ECG, sleep, recovery, stress, cycle tracking, vital alerts. Competitors charge monthly for less.
HSA / FSA
HSA/FSA eligible in the US
Pay with pre-tax dollars and keep roughly $90 of this order. We send the documentation for your records.
How it works
Pay with pre-tax dollars from a Health Savings or Flexible Spending Account. We send the documentation you need for your records.
By the numbers
140+Biosignals tracked
13+Health features
8daysDays of battery
3gGrams of titanium
Worldwide shippingon any non-discounted order
14-day returnno questions asked
1-year warrantyextendable at checkout
24/7 supportreal people, same day
What it measures
Thirteen health tools, one ring.
Every core feature is included with the ring.
Latest estimate
Optimal
116/74 mmHg
Blood pressure
Pulse transit time between the ECG and PPG sensors, calibrated monthly to your own cuff.
Last night
Restorative
86/100
Sleep
Four stages, breathing rate and blood oxygen through the night, scored by morning.
Energy today
Steady
72%
Activity and energy
Energy across the day, not only the steps you counted.
Readiness
Ready
78/100
Recovery
HRV and resting heart rate against your own baseline, not a population average.
Alerts this month
All clear
2reviewed
Vital alerts
Free on every ring. Speaks up when something moves away from your normal.
Balance today
Calm
64/100
Stress
Where the load fell today, and whether to train or rest tomorrow.
Cycle day
Ovulation window
14of 29
Women's health
Cycle, fertile window and hormonal phase, read from nightly temperature.
Circular age
3 below actual
31years
Longevity
A biological age you can actually move.
Woke at
Light sleep
6:42am
Wake Up
A vibration at your lightest moment inside the window you set.
Taken on time
On track
94%
Medication reminder
A tap on the finger, logged whether or not the phone is near.
Live heart rate
Measuring
68bpm
Live measurements
Heart rate, oxygen and temperature on demand, in ten seconds.
Session
Coherence 6/min
4:00min
Guided breathing
Paced breathing at six a minute, with HRV as the read-out.
See it work
Forty seconds, and a rhythm you can read.
Single-lead ECG · press to record
0:00
Sinus rhythm
No signs of atrial fibrillation
Two months in
What our users experienced over 2 months.
86%Slept better
92%More energy
79%Sharper focus
The differentiator
A clinical reading, on demand.
Why the finger
The arteries are closer here than a wrist can reach.
Which is why a ring can take a single-lead ECG in forty seconds, hold a clean signal through the night, and estimate blood-pressure trends a watch cannot. Everything Circular does follows from where it sits.
Thirty seconds at your finger, screened for atrial fibrillation, exported as a PDF your cardiologist can actually read.
Advanced health features
Every signal your body gives, translated.
Tracked, analysed and turned into guidance you can act on.
ECG + AFib detection
Track your heart rhythm with medical-grade technology and catch signs of arrhythmia before symptoms appear.
Kira coaching
Your AI health coach turns complex data into clear, actionable tips tailored to your lifestyle.
Sleep tracking
Monitor sleep stages, breathing and oxygen levels to understand how well your body recovers overnight.
Ring versus wrist
Smaller, lighter, and still on at 3am.
Circular Ring
Wrist tracker
Weight
3 g
45 g
Thickness
2.55 mm
11 mm
Battery
8 days
18 hours
Worn to sleep
Every night
Charging
Screen to check
None
Always
Wrist figures are typical for a mainstream smartwatch.
How it is made
Drawn, machined, then worn by the people who built it.
Titanium body with a PVD finish, hypoallergenic inside, 2.55 mm thick. Every algorithm is validated against clinical reference hardware, and every engineer on the team wears the ring — which is how the bugs get found before you do.
2.55mmThickness
7.8mmWidth
3gWeight
IP68Water rating
Designed not to distract
No screen. No buzzing. Eight days between charges.
Four grams of titanium with a PVD finish, 2.55 mm thick, hypoallergenic inside. Waterproof enough for the shower, the pool and the rain — worn through sleep without you noticing it.
Battery
Eight days on, thirty minutes off.
8days of wear
30minutes to full
Power mode. Around five days in performance mode, with high-frequency measurement.
Kira
Data is not the product. Understanding is.
The app
You wear the ring. Kira does the reading.
The ring captures the signals; the app turns them into plain sentences. Kira watches for changes in your vitals, flags early warning signs, and tells you what to do about today — no dashboard to decode.
Four finishes
Silver, obsidian, gold, rose gold.
The same ring underneath. Pick the one you would wear without thinking about it — the sensors, the battery and the features are identical across all four.
In the box
What arrives.
Circular Ring 2
Titanium, four finishes, nine sizes.
Wireless charging case
Protects, powers and travels with it.
USB-C cable
For the case. Thirty minutes to full.
Cleaning cloth
Keeps the sensors and the finish clear.
App access
iOS and Android, with the digital user guide.
Specification
Four grams of titanium.
BodyTitanium, hypoallergenic interior
Size2.55 mm thick, 7.8 mm wide, 3 g
SizesUS 6-14
Battery8 days power mode, 5 days performance
Charging30 minutes, wireless case
SensorsECG, PPG, temperature, 3-axis accelerometer
ConnectivityBluetooth Low Energy, airplane mode
CompatibilityiOS and Android
ComplianceGDPR and HIPAA
Who wears it
On the grid, on the court, in the clinic.
Drivers, athletes and clinicians wear the same ring you do — the same sensors, the same app, no professional edition.
Formula 1 and IndyCar driver
NBA player
Consultant cardiologist and electrophysiologist
Questions
The ones that matter.
No. Every core feature is included with the ring: ECG, four-stage sleep, energy, smart alarm, vital alerts, guided breathing, stress, chronotype, cycle tracking, activity, HRV, temperature, blood oxygen and live measurement. A small number of advanced screens are premium, and can be unlocked with coins you earn by wearing the ring rather than with money.
Choose the sizing kit. We post a set of replica rings in every size — wear the one that fits for a day, tell us which it was, and your ring ships. Nothing more to pay. If you already know your size, pick it and we ship straight away.
Sensors and algorithms are validated against clinical reference equipment, and readings update roughly every two minutes. Blood pressure is a wellness trend rather than a diagnosis, and asks for a monthly calibration against an ordinary cuff.
Yes. Showers, swimming and daily wear are all fine.
Around eight days in power mode and four to five in performance mode, from a thirty-minute wireless charge.
Encrypted from ring to app to cloud, on servers that meet GDPR requirements, deletable by you at any time. We never sell or share health data.
Owners
What people say.
Total 5 star reviews: 135 Total 4 star reviews: 29 Total 3 star reviews: 14 Total 2 star reviews: 7 Total 1 star reviews: 5
86%would recommend this product
Slide 1 selected
190 reviews
- MSMichal S.Verified BuyerRated 5 out of 5 stars1 month agoCircular Ring 2 Gold size 14
A wonderful ring—great design and functional. I recommend it to anyone looking for something unique that also acts as a guardian of their health.
CCircular1 month agoHi Michal
Thank you so much for the review :)
We're thrilled to hear that you love your Circular Ring 2 and that it's helping you stay on top of your health.
Thanks again for the recommendation, and enjoy your ring!
- ANAlbert N.Verified ReviewerRated 5 out of 5 stars1 month agoEarly Backer Perspective
I backed this project early and waited years for my ring. I watched the internet assault this company with immense ferocity usually reserved for politics. To see them pulling through that is impressive. I work construction and beat the absolute hell out of my ring and have never had an issue with it. Sure the app was janky at first and the lack of background syncing is still bothersome, but there are active updates and improvements and again for me this was a crowdfunding project. I like where the app is going now and am excited for more potential growth from a company clearly full of perseverance.
CCircular1 month agoHi Albert,
Thank you so much for this amazing review and for your long-standing support as an early backer! :)
We truly appreciate your understanding of the crowdfunding journey and your recognition of our team's perseverance. It's awesome to hear that your ring is proving its durability on the construction site every day!
We know the app is a work in progress, and we are fully committed to rolling out active updates, improving the background syncing, and delivering the experience you deserve. Thank you for sticking with us and being a part of our growth
- JAJanice A.Verified BuyerRated 5 out of 5 stars2 months agoBeautiful design
Beautiful color and high level design. Great fit and works well.
CCircular2 months agoHi Janice,
Thank you so much for the review!
We are absolutely delighted to hear that you love the beautiful design and color of your ring, and that the fit and performance are working perfectly for you :)
Thank you for being a valued member of the Circular community.
- CClemensVerified ReviewerRated 4 out of 5 stars4 months agosync is finally stable but the foundation is now right
I have the (black, size 11) ring since nov14th '25 - so here is my second review now - with plenty of real world usage
a) integration with apple health works, albeit there is more data points that should be synced (both ways DoB, weight, etc) rather then me adding this to my profile by hand :(
b) I wear the ring almost 24/7 including during all sorts of sports - and for me it works well, There is two last bugs that are annoying:
- after 50 sessions the sport session overview (See picture) does not list any new sessions (while syncing new ones into apple health, so I guess no-one ever tried this)
- I usually start a sport session, then stop the app / bluetooth - as I am anyway away from my phone, and when I am done, bluetooth on, app start - In this case the (live) pulse diagram does not show up in the sports session view anymore, albeit data being recorded - I guess it's a UI glitch
c) On sleep - this can / has to be improved - because it's hindering my lifestyle quite a bit. There is no way to tell the ring / app - I have woken up - go start measuring NOW (e.g. hrv, ..). Instead the ring figures it out itself and this needs time (~20?+ minutes sometimes more.. ). So I need to wait (and cant do sports), .. otherwise data is just murx
d) Albeit being promised, still NO Blood glucose or blood pressure. There is plenty discussion on kickstarter on the (commercial) model that is used (Freemium, the circular coins that you earn by wearing the ring). And it am not challenging…
CCircular3 months agoHi Clemens,
Thank you for this detailed and constructive 4-star review! We are glad to hear that sync stability has improved and that your Circular Ring 2 is holding up well during your 24/7 usage and sports activities :)
We’ve noted your specific feedback and have some updates for you:
Apple Health Integration: Currently, certain "personal" data points like Date of Birth and Weight must be added manually for privacy and profile accuracy, but we are looking into ways to improve this integration.
Sport Session UI: The bug regarding the session limit is now on our radar for a future app update.
Sleep/Waking Logic: We understand the need for faster data processing upon waking, and our team is actively working on a way for you to manually tell the ring that you are awake
Blood Glucose & Blood Pressure: We are working hard on the development of these features. We want to ensure the core experience is perfect first, but these are definitely still planned and remain a priority on our roadmap.
Your feedback is essential in helping us move from a "good" foundation to a "great" one. Thank you for being part of the Circular community!
- SSégolèneVerified ReviewerRated 5 out of 5 stars4 months agoPerfect balance of style and performance
I love using my ring to track my sleep. It’s incredibly comfortable to wear and has a sleek, aesthetic design. A truly great partner for maintaining my health.
Prevention beats treatment. That is the whole reason this exists.
The range
