Measure your ring size, online.
A ring sizer calibrated to your screen — no ads, no account. Four methods, one precise answer, and free resizing if it ever matters.
Lay a bank card flat on the screen, then adjust the outline until it matches the card exactly.
Keep the card flat, not tilted. Calibration is saved on this device.
Why it is more precise than the rest
Bank-card calibration — an object with a standard ISO size, not a rough on-screen image.
Quarter US sizes, converted to UK, EU and JP in real time.
Measurements stay on your device: nothing is uploaded.
Full conversion chart
Size 3 to 13 in quarter increments, with diameter and circumference in millimeters.
| US / CA | UK / AU | EU / ISO | JP / CN / KR | Ø mm | mm |
|---|---|---|---|---|---|
| 3 | F | 44 | 8 | 14.1 | 44.3 |
| 3¼ | G¼ | 45 | 8 | 14.3 | 44.9 |
| 3 | G | 46 | 9 | 14.5 | 45.6 |
| 3 | H¼ | 46 | 9 | 14.7 | 46.2 |
| 4 | H | 47 | 7 | 14.9 | 46.8 |
| 4¼ | H | 47 | 7 | 15.1 | 47.4 |
| 4 | I | 48 | 8 | 15.3 | 48.1 |
| 4 | I | 48 | 8 | 15.5 | 48.7 |
| 5 | J | 49 | 9 | 15.7 | 49.3 |
| 5¼ | J | 49 | 9 | 15.9 | 50 |
| 5 | K | 51 | 10 | 16.1 | 50.6 |
| 5 | K | 51 | 10 | 16.3 | 51.2 |
| 6 | L | 52 | 12 | 16.5 | 51.8 |
| 6¼ | L | 52 | 12 | 16.7 | 52.5 |
| 6 | M | 53 | 13 | 16.9 | 53.1 |
| 6 | M | 53 | 13 | 17.1 | 53.7 |
| 7 | N | 54 | 14 | 17.3 | 54.3 |
| 7¼ | N | 54 | 14 | 17.5 | 55 |
| 7 | O | 56 | 15 | 17.7 | 55.6 |
| 7 | O | 56 | 15 | 17.9 | 56.2 |
| 8 | P | 57 | 16 | 18.1 | 56.9 |
| 8¼ | P | 57 | 16 | 18.3 | 57.5 |
| 8 | Q | 58 | 17 | 18.5 | 58.1 |
| 8 | Q | 58 | 17 | 18.7 | 58.7 |
| 9 | R | 60 | 18 | 18.9 | 59.4 |
| 9¼ | R | 60 | 18 | 19.1 | 60 |
| 9 | S | 61 | 19 | 19.3 | 60.6 |
| 9 | S | 61 | 19 | 19.5 | 61.3 |
| 10 | T | 62 | 20 | 19.7 | 61.9 |
| 10¼ | T | 62 | 20 | 19.9 | 62.5 |
| 10 | U | 63 | 22 | 20.1 | 63.1 |
| 10 | U | 63 | 22 | 20.3 | 63.8 |
| 11 | V | 65 | 23 | 20.5 | 64.4 |
| 11¼ | V | 65 | 23 | 20.7 | 65 |
| 11 | W | 66 | 24 | 20.9 | 65.7 |
| 11 | W | 66 | 24 | 21.1 | 66.3 |
| 12 | X | 67 | 25 | 21.3 | 66.9 |
| 12¼ | Y¼ | 68 | 17 | 21.5 | 67.5 |
| 12 | Y | 68 | 18 | 21.7 | 68.2 |
| 12 | Z¼ | 69 | 18 | 21.9 | 68.8 |
| 13 | Z | 69 | 18 | 22.1 | 69.4 |
Free resizing, 60-day returns, and a production size check by the Belaroq team.
Ring sizer questions, answered
Is the online ring sizer accurate?
Yes. After calibrating with a bank card (the standard ISO format of 85.6 × 53.98 mm), the screen shows real millimeters. Accuracy depends on careful alignment; confirm non-resizable pieces with Belaroq before production.
Why calibrate the screen with a bank card?
Every screen renders pixels at a different scale. A bank card has a standardized size, which lets us convert pixels into real millimeters on your device.
How do I measure without an existing ring?
Use the paper strip method: wrap a narrow strip around the base of your finger, mark the overlap, flatten it, and compare it against the calibrated on-screen ruler.
When should I measure my finger?
In the evening at room temperature. Avoid mornings, right after exercise, after salty meals, or in cold weather, because finger size shifts through the day.
What if I am between two sizes?
Choose the larger size for comfort, especially for wide bands (6 mm and up), which feel tighter. Belaroq confirms the production size on request.
What if the delivered size does not fit?
Belaroq includes free resizing, and the 60-day return policy covers sizing mistakes, so you never have to live with an uncomfortable ring.
Is my measurement private?
Yes. Calibration and measurement happen entirely in your browser; no measurement data is sent to a server.
Does the ring sizer work on a phone?
Yes. Open this page in your phone's browser, calibrate with a bank card, then place your ring or paper strip directly on the screen.