Smart Ring Size Guide - How to Find the Size That Fits You

Choosing the right size for a smart ring is crucial for both comfort and accurate sensor readings. A ring that's too loose rotates on the finger and gives unreliable measurements. A ring that's too tight is uncomfortable and hard to remove. Since smart ring sizes don't follow regular ring sizes, you can't rely on your usual size.

To ensure the best fit, we recommend measuring your finger with our sizing kit before ordering your ring. It's the safest way to get it right - and you avoid hassle with exchanges and returns.

Find Your RingConn Size by Circumference

RingConn sizes don't follow regular ring sizes, and measurements vary slightly between generations. Measure your finger's circumference, find your range in the table, and read your size.

💡 Tip: The numbers are the finger's circumference. Always order your sizing kit and wear the test ring for at least 24 hours — even at night — before ordering the actual ring. Fingers change size throughout the day.

Size (US)	Gen 3 – Circumference	Gen 2 / Gen 2 Air – Circumference
6	≤ 52.1 mm	≤ 51.6 mm
7	52.2–54.6 mm	51.7–54.5 mm
8	54.7–57.2 mm	54.6–56.9 mm
9	57.3–60.3 mm	57.0–59.5 mm
10	60.4–62.7 mm	59.6–62.3 mm
11	62.8–65.1 mm	62.4–64.8 mm
12	65.2–67.8 mm	64.9–67.0 mm
13	67.9–70.3 mm	67.1–69.5 mm
14	70.4–72.3 mm	69.6–72.0 mm
15	72.4–74.9 mm	– (only Gen 3)

Step 1: Order Your Sizing Kit

Order your sizing kit before buying the ring. The set includes plastic measuring rings in all sizes, so you can find your perfect fit at home.

Add the sizing kit to your cart for 1 kr. - or buy it separately.
You will receive the kit in 1–3 business days.
Measure your finger as described in step 2 below.

Step 2: Test Your Size

Follow these steps to find your most accurate size:

Choose a finger. The ring fits all fingers on both hands. For best measurement accuracy, we recommend the index finger - the middle finger is a good alternative for comfort.
Position the ring correctly. The sensor side should face the fingertip for accurate measurement.
Wear for 24 hours. Fingers swell and shrink throughout the day due to temperature, activity, and sleep. Wear the test ring for a full day - including at night - for the most accurate result.

A well-fitting ring feels comfortable and stays in place without rotating. It should fit slightly snugly but never hurt, restrict blood flow, or be hard to remove. If it does, go up a size.

Step 3: Order the Right Ring

Now that you've found your size, you're ready to order your smart ring with peace of mind. Remember: if you bought the sizing kit, the ring can be returned unopened if you change your mind.

Frequently Asked Questions

What if I'm between two sizes?

Choose the smaller of the two. It provides the most accurate fit and ensures the ring doesn't rotate on your finger.

Can I borrow a sizing kit from someone else?

Yes. If someone you know already has a kit, you can use it to find your size. Once you've confirmed the size, you can order the ring directly with the correct size selected.

Why does the actual ring feel different from the kit?

This is completely normal. The plastic sizer has a slightly rougher interior, while the actual ring has a smoother surface and therefore slides on and off more easily — even at the same size. Therefore, the test ring should fit securely and slightly snug, not loose.

Should I test my size at different times of the day?

Yes, it is recommended. Fingers change size depending on time, physical activity, temperature, fluid intake, and sleep. Wear your sizer for at least 24 hours including sleep for the most accurate result.

Is it okay if the sizer ring leaves light marks?

Light marks can be normal, especially after sleep or when fingers naturally swell. But the ring should never hurt, restrict blood flow, or be hard to remove. If it does, adjust up a size.

Do you have a 3D printer?

Then you can download our sizer file and print your own measuring ring. Print at 100% scale for correct size. Download the 3D model file here.