By Mohit Patel, Marketing Specialist, Tailor Size Guide
International conversions Nov 14, 2026 3 min read
Ring Size Conversion: US to UK
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Add Tailor Size Guide as a preferred source on GoogleUS ring sizes use numbers 3-13 with halves. UK uses alphabet letters A-Z. UK letters skip every other letter for half sizes (J 1/2).
The Chart
| US | UK | Diameter (mm) | Circumference (mm) |
|---|---|---|---|
| 4 | H | 14.9 | 46.8 |
| 5 | J 1/2 | 15.7 | 49.3 |
| 6 | L 1/2 | 16.5 | 51.9 |
| 7 | N 1/2 | 17.3 | 54.4 |
| 8 | P 1/2 | 18.1 | 57 |
| 9 | R 1/2 | 19 | 59.5 |
| 10 | T 1/2 | 19.8 | 62.1 |
| 11 | V 1/2 | 20.6 | 64.6 |
| 12 | X 1/2 | 21.4 | 67.2 |
| 13 | Z 1/2 | 22.2 | 69.7 |
FAQs
How do half sizes work in UK letters?
UK uses 'J 1/2' for the half size between J and K. Some manufacturers skip half sizes; others use them. Always check the brand's specific chart.
What if my US size isn't on the chart?
US ring sizes go from 1 (children) to 16 (extra large). The chart above covers most adult sizes. For unusual sizes, divide circumference by 3.14159 to get inner diameter, then match to brand's chart.
Need this on your store?
Tailor Size Guide ships pre-built size charts for Shopify.