Articles on: Ring

How to know my Circular Ring size?

Please read our sizing page


The Circular ring sizes fit the standard ring sizes. If you already know your ring size, Circular sizes will be the same. You can also go to any jeweler to ask for your US equivalent finger size.


If the size does not fit when you receive your ring, you'll have 14 days upon delivery to change it for free (except shipping) if your ring is unworn and intact.


For Generation 2 (Circular Ring 2)


The ring comes in 9 different sizes from US 6 to US 14. We don't do half sizes. The sizing follows standard US ring sizes, so if you already know yours, Circular will match it exactly.


We offer different options to find your size, from the most accurate to the least accurate method.


  1. The most accurate way to find your size is with our Sizing Kit. This kit includes a full set of plastic rings in every size, so you can try them on at home before receiving your actual Circular Ring.

The kit costs $5, and you can order yours separately here or directly with your ring.


  1. If you have access to a 3D printer, you can print your sizing rings here.


  1. Comparison of Circular size against other smart rings:


  • Circular ring 2 size = Oura ring Gen 3 size
  • Circular ring 2 size = Samsung ring size
  • Circular ring 2 size = Ringconn ring size
  • Circular ring 2 size = Ultrahuman ring size + 1


Size 6 = 16.90 mm diameter

Size 7 = 17.70 mm diameter

Size 8 = 18.50 mm diameter

Size 9 = 19.30 mm diameter

Size 10 = 20.10 mm diameter

Size 11 = 20.90 mm diameter

Size 12 = 21.70 mm diameter

Size 13 = 22.50 mm diameter

Size 14 = 23.30 mm diameter


  1. An easy-to-use digital sizing tool to help you find the right fit for your smartphone.


Click here if you're on Mobile.


Scan this QR code with your Mobile if you're on a computer.



You will find 3 options:


  1. AI-based Photo Sizing with a reference: Take a picture of your hand with a reference card.
  2. Ring Comparison: Place a ring you already own on screen to match with Circular’s size guide.
  3. Size Conversion Guide: Use our mm Guide for equivalency.


If you have issues with the AI photo sizing tool


Make sure to meet these requirements for the picture:

✔️ Good lighting

✔️ Plain background

✔️ Spread fingers

✔️ No rings

✔️ Follow the example image closely in terms of hand-phone distance


NOTE: Make sure to get __multiple __measurements with the same results.

NOTE: If you’re unsure of the accuracy you can visit any local jeweler to find your US equivalent finger size. The Circular Ring will match it exactly.


For Generation 1


The ring comes in 8 different sizes from US 6 to US 13. One of them should fit. We don't do half sizes.


You have the option to receive a sizing kit before delivery to confirm your size. It costs $5. You can get one here.


Here is the free Circular sizing guide to be printed


Here is the free Circular rings to be 3D printed


The sizing rings are made of plastic and may be sharper on the edge and on the charging pins compared to the real ring.


Here are some wearing recommendations: You can wear Circular on any finger. It has to fit comfortably. If you're between sizes, we usually recommend choosing the bigger size that fits. If you have big knuckles, choose the smallest size that slides over your knuckle. It’s better tight than loose.


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 that the three middle fingers give the most accurate readings.


Finger size can vary depending on the time of the day, especially in the morning/evening when your fingers are slightly larger.

Updated on: 02/09/2025

Was this article helpful?

Share your feedback

Cancel

Thank you!