Free Online Ring Sizer
Find your ring size in about a minute, right from your phone. Calibrate the screen with any bank card, then match a ring that already fits. Sizes shown in the US/Canada scale Canadian jewellers use, with the measurement in mm.
Online ring sizer
Calibrate once with any bank card, then size a ring right on your screen. A phone works best.
Stand any bank or credit card upright against the outline below, then drag the slider until the outline is exactly as tall as your card. Every card is the same standard size, 85.6 mm tall this way.
Ring size chart (US/Canada)
Inside diameter is measured straight across the inside of the ring. Inside circumference is the distance around, which is what a paper strip gives you.
| US/Canada size | Inside diameter | Inside circumference |
|---|---|---|
| 3 | 14.1 mm | 44.2 mm |
| 3.5 | 14.5 mm | 45.5 mm |
| 4 | 14.9 mm | 46.8 mm |
| 4.5 | 15.3 mm | 48.0 mm |
| 5 | 15.7 mm | 49.3 mm |
| 5.5 | 16.1 mm | 50.6 mm |
| 6 | 16.5 mm | 51.9 mm |
| 6.5 | 16.9 mm | 53.1 mm |
| 7 | 17.3 mm | 54.4 mm |
| 7.5 | 17.7 mm | 55.7 mm |
| 8 | 18.1 mm | 57.0 mm |
| 8.5 | 18.5 mm | 58.2 mm |
| 9 | 18.9 mm | 59.5 mm |
| 9.5 | 19.4 mm | 60.8 mm |
| 10 | 19.8 mm | 62.1 mm |
| 10.5 | 20.2 mm | 63.3 mm |
| 11 | 20.6 mm | 64.6 mm |
| 11.5 | 21.0 mm | 65.9 mm |
| 12 | 21.4 mm | 67.2 mm |
| 12.5 | 21.8 mm | 68.5 mm |
| 13 | 22.2 mm | 69.7 mm |
| 13.5 | 22.6 mm | 71.0 mm |
The printable version
Print our free sizer sheet, lay a ring over the circles, and read off your size. It includes a built-in scale check so you know the print came out true to size.
Want the full walkthrough, secret-sizing tricks, and UK/EU conversions? Read our Canadian ring size guide. Planning the wedding too? Our free planning tools keep your guest list, budget, and vendors in one place.