CIRCULAR startup guide

Welcome! Your journey to better
health starts here.

This startup guide will take you through all the steps to setup your Circular ring and App.

01. getting started

Setup your Circular ring with your charger.

Charge your ring

You first need to wake it up by placing it on the charger and charge your ring to 100% for at least 45 minutes for battery calibration purpose. To do so, you need to place both magnetic pins of the ring on those located on your charger.

Understand charging

You can plug the charger into a power source (laptop, power bank, phone...). The connector needs to be USB-C.

Look out for the charger's LED

The LED of the charger will fade in and out when the ring is charging and the LED will turn off when the battery of the ring is full.

02. APP and use

Start using your Circular Ring

Install the app

Search for "Circular ring" on the App Store or Google Play. Once dowloaded, follow the instructions to create an account and to pair your ring!

Wear the ring 24/7 & synch your data

Once you have a ring paired with your account, you are all set! The ring will automatically start tracking your metrics as soon as it detects that you are wearing it.

To see your data in the app, make sure that a sync between the ring and the app has been done. You will see a loading progression bar 5 seconds after you connect to your ring that indicates your data is downloading. If that is not the case you can force a synchronization by swiping down on the home page.

03. wear instructions

How to wear your ring

You can wear Circular on any finger. The three middle fingers give the most accurate readings but you can still wear it on other fingers.

It is best to wear Circular on the fingers of your non-dominant hand. Eg: If you are right-handed, wear it on your left hand.

Note: You will notice that the Circular ring is slightly larger than a traditional ring and that's because it has a vibration motor and a mechanical button that will allow for additional features.
The flat part of the ring should be
towards the palmar side of your hand
(bottom of your finger). 
The button of the ring should be accessible
with the thumb of your same hand. Do not press the
button with your nail to avoid deterioration.
To remove your ring

In case the ring gets stuck on your finger:

1. Hold your hand up above your heart until the blood pressure lowers and then try to remove your ring.

2. Push the bottom of your ring towards your finger, it should create a space above your finger, between your finger and your ring. Then pull the ring to take it out while continuing pressing your ring towards your finger.

3. Use soap or gel and slowly twist the ring to remove it.

Watch out, finger size can vary through the day, your fingers may swell in the morning or evening!
04. Outer-shell

How to change your Outer-shell

The ring is made so that the outer-shell can turn only on one side of the button. Rotate the shell so that it goes over the button. Once this is done you can dislodge it from the ring. Under no circumstances should you ever use force to remove the outer-shell, as this could break the edges of your ring.

IMPORTANT NOTE: If for any reason, your outer-shell seems as not fitting your ring and is spinning around your ring, please contact the support at so that we can assist with a replacement.

It may also be possible that your Outer-shells has a peak of metallic material on the inside in the contact with the Circular Ring. If this is the case, we advise you to sand it down or remove it with a scrapping tool, otherwise you risk scratching your ring.
04. CARE

Care and maintenance

Water Resistance

Do not submerged the ring under water. It's only suitable for light water exposure like rain, showering or washing hands.


In order to clean your ring, use a soft cloth or hand wash with mild soap and water on the cloth.

It is not recommended to let moisture stagnate between the ring and the finger after wearing the ring if it was in contact with water. Please remove the ring from your finger and dry your finger and the inside of the ring with a cloth before wearing it again.

Scratch resistance

The Circular changeable Outer-shells may get scratches against harder metal jewelry or other objects made of harder materials in contact with.

Carrying weight

It is not recommended to use the ring when carrying weight. Damage may occur to the ring and button.

Button use

Do not press the button with your nail to avoid deterioration. The button must be pressed with human fingers only.

Determining your current battery level 

Calibration of the battery percentage level

Charge your ring to 100% for at least 45 minutes when you receive it for battery calibration purposes. Without that, the app may show incorrect battery level.

My ring has reached 0% battery

Charge your ring. If your ring has reached 0% battery, please connect the app to your ring before wearing it again. If you don't, your ring won't acquire data.

Checking the ring battery level when I wear the ring

By logging into your Circular app and looking at the top-right corner of the home page. You can also click on it to see the battery percentage level.

Checking the ring battery level when I charge the ring

If your ring is on the charger and is fully charged, the charger LED will turn off.

Battery percentage curve

The battery percentage may not be linear. You can get longer use from 40% to 5% than from 100% to 40%.

Charging your Circular ring

IMPORTANT NOTE: If your ring has reached 0% battery, please connect to your ring with the app. If you don't do it, your ring won't acquire data.

How to charge my ring

The Circular ring is held magnetically to the charger. To charge your Circular ring: 
1. Place the magnetic contact pins from your Circular ring on the charger’s pins. Be sure that it is right in place and that both connectors of your ring are in contact with the charger's pins.
2. Plug the charger dongle into a USB-C port on your computer or an adaptor on any plug.
3. Double check if the led of the charger blinks, which indicates that it is charging. Your ring is fully charged when the led stops blinking.

It takes 45 to 60 minutes to fully charge your ring when it is empty.

Some pro tips for charging success 

1. Try placing the ring on the charger first, then plugging in the USB port. If you do not see the LED blinking, try lightly moving the ring on the charger. 

2. Try taking the ring off the charger and then putting back. 

3. If you still do not see the LED, try flipping the ring 180 degrees (like spinning a penny, not rotating like a wheel) so the opposite charging contact connects. If you still do not see the LED, try cleaning the contact pins of your charger and your ring using warm water and soap, then drying with a soft cloth.

4. If you still do not see the LED, try a different power source or other adapter/charger.

5. When charging a Circular device using a wall outlet, it is recommended that a premium brand AC adapter should be used. Some off-market adapters will prevent the ring from reaching the charging state. 

6. Charge your ring at room temperature. Avoid charging in your cold car, garage, or a room that is too hot. 

7. After a firmware update, the battery display in your Circular app can be off. To make sure the displayed battery charge is accurate, please fully charge your ring again.
07. Features

What your Circular ring can do for you

Smart Alarm with vibrations

- Wake Up score 
- Smart Alarm
- Smart Snooze

Sleep analysis

- Sleep quality score
- Chronotype
- Total sleep duration
- Real sleep duration
- Disturbances
- Tranquility
- Circadian rhythm
- Sleep stages including deep and rem sleep
- Sleep latency
- Sleep debt 

Activity analysis

- Energy score
- Active minutes
- Steps
- Distance
- Total calories burned
- Cardio points
- VO2 max estimate
- Max heart rate
- Body recovery
- Activity volume
- Resting heart rate
- Heart rate
- Breathing rate
- Blood oxygen
- Heart rate variability
- Temperature variation 

Live measurement

- Heart rate
- Heart rate variability
- Blood oxygen 


Guided breathing

- Set of breathing exercices
- Resting heart rate during exercise
- Heart rate variability during exercise
- Breathing coherence during exercise

Vitals alerts

- Low heart rate vibration
- High heart rate vibration

Requirements for Use of the Circular Services

The full Circular experience requires Circular products, internet access to the Mobile App and Websites, and other required software (if any). Periodic updates to any of these elements may be required for improved performance, and the performance of the whole may be affected by the performance of any of these elements.

You are responsible for obtaining your own internet access and mobile device to access the Circular Services.
09. safety

Safety Information

Health diagnostic

Please note that Circular is not intended to diagnose, treat, cure or prevent any disease or medical condition without the assistance of a health professional. The information and guidance provided by Circular are there for informational purposes only and cannot replace the services of health professionals or physicians. You should always consult a health professional if you have any questions regarding any changes you intend to make to your sleep or activity or regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read through Circular services.

Circular is not responsible for any health problems that may result from information or guidance you learn through the Circular services. If you make any change to your sleep or activity based on the Circular services, you agree that you do so fully at your own risk.


Please be cautious that the ring or any other Circular product you are wearing does not get caught on fixed structures or heavy objects when moving yourself or moving said heavier objects.

Do not try to open the ring or puncture the ring or its battery.

Electricity safety

Like with all rings made of metals, be careful when handling batteries when you are wearing the ring. If the electrodes of a battery are in contact with the ring, the battery may short circuit.


Keep the ring away from children. This product is not intended for individuals under the age of 18. Seek immediate medical attention if you know or suspect that a child has swallowed the ring.

Heat exposure

Do not leave the ring exposed to prolonged heat, such as the sun.

Skin issues

You may have yellow or brown marks on your finger where the charging pins of the ring lie. This is due to the use of gel, hot water or salted water that rubs off the gold color of the contact pins. These marks are non permanent and will disappear. It occasionally happens and it is easily removed by washing your hands.

However if you experience redness or skin irritation on your finger due to the ring or any Circular product, remove it immediately. If symptoms persist longer than 3 days of not using your Circular product, please contact a dermatologist.

Airports, Secure Buildings, Magnetic Scans 

The magnetic field created by metal detecting gates present at airports or entrances to secure buildings are known to harm electronic equipment, such as laptops, cell phones and the Circular ring.

Security wands create a magnetic pulse that can damage electronic devices. Even a single exposure can impact your Circular ring in a way that's not immediately visible. It is recommended to send all your electronic devices through the x-ray scanner with your carry-on.
10. Accuracy

Factors that may impair data accuracy

Circular tests accuracy against medical grade gold standard device while building each of the monitored metrics. Pulse oximeter for SpO2, holter monitor for heart metrics and foot pods which are the best source of “truth” for steps.

Sport sessions
For certain exercises, such as Crossfit, weightlifting or riding a bike, it may be difficult to auto-detect sport sessions. This is because when you’re lifting heavyweights for an extended period of time or gripping something tightly, it’s more difficult for the heart rate sensor to get a clear reading. This is because the sensor is being pushed against your skin which becomes compressed and harder to see through. 

It is recommended to turn the flat part of the ring on the top of your finger during an activity as Crossfit, weightlifting or riding a bike. Another factor that can impair signal quality is temperature, as in cold weather blood can retreat from your fingers, which can also make it difficult for the heart rate sensor to get a clear reading. 

Heart metrics 

Regarding heart metrics, Circular will only report average measurements per minute, so if the max HR is not sustained over a span of a minute or so, the minute average for that time will be lower than what other trackers can report, as they can report heart rate with higher temporal resolution. There is a trade-off between higher temporal resolution and battery life. 

Steps during transportation

The vibrations of your transportation on the road or on the rail line may sometimes transfer to your hand / finger and look like steps to the ring. Especially when your ring-wearing hand is resting on a surface or the steering wheel for example.
11. liability

Limitation of liability

In no event will Circular or any of its affiliates be liable for direct, indirect, incidental, punitive, or consequential damages (including without limitation those resulting from lost profits, lost data, or business interruption) arising out of the use, inability to use, or the results of the use of the Circular services, whether such damages are based on warranty, contract, tort or any other legal theory and whether or not Circular has been advised of the possibility of such damages. The aggregate liability of Circular, arising from or relating to the Circular services (regardless of the form of action or claim, e.g. Contract, warranty, tort, strict liability, negligence, or any other legal theory) is limited to €100. Circular’s affiliates, providers, and partners have no liability whatsoever arising from the website. In some locations, applicable law may not allow certain of the limitations described above, in which case such limitations will apply to the maximum extent allowed by such applicable law.

Support and Questions

If you have any questions about getting started with or using your ring, mobile app and any other Circular services, or you have any issues with your product, please refer to the FAQs at

If you can’t find what you are looking for, send us an email to
13. terms

Terms of use

Your use of the Circular products and services is subject to our Terms of Use, available at, and Privacy Policy available at
14. ip

Intellectual Property Rights

Circular logo © and Circular™ are trademarks or registered trademarks of Circular Patented and patents pending. All rights reserved. You are not granted, by implication or otherwise, any license or right to use any marks appearing on Circular Services. One or more patents owned by Circular (or patents licensed from third parties) apply to the Circular Products and to the features and services accessible via the Circular Services maintained by Circular.

Regulatory & Safety Notices


Circular has not approved any changes or modifications to this device by the user. Any changes or modifications could void the user’s authority to operate equipment. 

California Proposition 65

WARNING: This product may contain chemicals known to the State of California to cause birth defects or other reproductive harm. For more information go to

USA: Federal Communications Commission (FCC) statement

This device complies with FCC part 15 FCC Rules. Operation is subject to the following two conditions: 

1. This device may not cause harmful interference and 

2. This device must accept any interference received, including interference that may cause undesired operation 

FCC Warning 

Changes or modifications not approved by Circular could void the user’s authority to operate the equipment. 

Note: This equipment has been tested and found to comply with the limits for a Class B digital device, pursuant to part 15 of the FCC Rules. These limits are designed to provide reasonable protection against harmful interference in a residential installation. This equipment generates, uses, and can radiate radio frequency energy and, if not installed and used in accordance with the instructions, may cause harmful interference to radio communications. However, there is no guarantee that interference will not occur in a particular installation. If this equipment does cause harmful interference to radio or television reception, which can be determined by turning the equipment off and on, the user is encouraged to try to correct the interference by one or more of the following measures: 

• Reorient or relocate the receiving antenna 
• Increase the separation between the equipment and receiver 
• Connect the equipment into an outlet on a circuit different from that to which the receiver is connected. 
• Consult the dealer or an experienced radio/TV technician for help. 

This device meets the FCC requirements for RF exposure in public or uncontrolled environments. 


RF exposure safety

This product is a radio transmitter and receiver. It’s designed not to exceed the emission limits for exposure to radio frequency (RF) energy set by the Federal Communications Commission.This transmitter must not be co-located on operating in conjunction with any other antenna or transmitter.

Canada: Industry Canada (IC) statement 

This device meets the IC requirements for RF exposure in public or uncontrolled environments. 

IC Notice to Users in accordance with RSS GEN Issue 5:

This device contains licence-exempt transmitter(s)/receiver(s) that comply with Innovation, Science and Economic Development Canada’s licence-exempt RSS(s). Operation is subject to the following two conditions:
1. This device may not cause interference.
2. This device must accept any interference, including interference that may cause undesired operation of the device.

IC: 29243-CIRCULAR110. 


This class B digital apparatus complies with Canadian ICES-003.

Cet appareil numérique de classe B est conforme à la norme Canadienne ICES-003.

European Union (CE) 

Declaration of Conformity with Regard to the EU Directive 2014/53/EU 

Circular is authorized to apply the CE Mark on CIRCULAR RING, thereby declaring conformity to the essential requirements and other relevant provisions of Directive 2014/53/EU and other applicable Directives.

Frequency range: 2402-2480 MHz
Max output power: 3.29 mW 

In order to satisfy the essential requirements of 2014/53/Eu Directive, the radio equipment is compliant with the following standards:

RF spectrum use: EN 300 328
EMC: EN 301 489-1, EN 301 489-17, EN 55032, EN 55035, EN 50566, EN 61000 

The conformity assessment procedure of Directive 2014/53/EU has been followed with the involvement of the following Notified Body:

Intertek Testing Services Hong Kong Ltd.2/F., Garment Centre, 576 Castle Peak Road,Kowloon, Hong Kong SAR, China.


This product is compliant with Directive 2012/19/EU. Please dispose used electrical and electronic equipment (WEEE) according to national laws and regulations with electrical waste. It should not be mixed with general household waste. 

United Kingdom (UKCA)

This product is compliant with the UK Conformity Assessment Radio Equipment Regulations 2017.
Australia and New Zealand

Compliant with the standard R&TTE 99/CE/05 Australia and New Zealand R-NZ
16. specifications

Specifications for your Circular products

Changeable Outer-shell materials

  • Resistant and high-grade alloy of stainless steel and carbon with high-end coating 

Inner-shell materials

  • Non-allergenic, nonmetallic clinical-grade biocompatible resin

Charger materials

  • High-end polymer 


  • 3 LEDs Oximeter sensor: Infrared, Red, and Green
  • 3-axis accelerometer
  • Digital temperature sensor

Input and Output active component

  • Mechanical push button
  • Vibration motor

Memory Capacity

  • Flash ROM memory (up to 10 days)


  • Rechargeable 24 mAh - 31 mAh Li-Ion battery, non-replaceable.

Battery life

  • Up to 4 days


  • 60 min of charging


  • Bluetooth Low Energy 4.2 to 5.0

Firmware Update

  • Automatic firmware updates via the Circular app. Bluetooth Secure DFU. 


  • Suitable for light water exposure like showering or washing hands.

Ring size & characteristics

  • 8 sizes: from 6 US to 13 US
  • 9 mm large x 2.8 mm wide
  • 5 grams

Operating temperatures

  • Usage: -10°C / 45°C
  • Charging temperature 10°C - 45°C
  • Discharging temperature 20°C - 60°C


  • CE
  • RoHS
  • FCC Class B digital device
  • CA Prop 65
  • UKCA
  • IC
  • R&TTE
  • R-NZ


  • GDPR & HIIPA & CCPA compliant
  • Data encryption, secure pairing of the ring and the app


  • Free app on iOS and Android
  • Compatible with  mobile devices that run iOS 11.0 or later, or Android 6.0 or later.