UK to US ring size
Convert a UK ring size to US in one step. Enter your UK size and read the US equivalent, or use the full chart below.
UK to US ring size chart
| UK size | US size | Diameter (mm) |
|---|---|---|
| F | 3 | 14.1 |
| G | 3.5 | 14.5 |
| H | 4 | 14.9 |
| I | 4.5 | 15.3 |
| J | 5 | 15.7 |
| K | 5.5 | 16.1 |
| L | 6 | 16.5 |
| M | 6.5 | 16.9 |
| N | 7 | 17.3 |
| O | 7.5 | 17.7 |
| P | 8 | 18.1 |
| Q | 8.5 | 18.5 |
| R | 9 | 19 |
| S | 9.5 | 19.4 |
| T | 10 | 19.8 |
| U | 10.5 | 20.2 |
| V | 11 | 20.6 |
| W | 11.5 | 21 |
| X | 12 | 21.4 |
| Y | 12.5 | 21.8 |
| Z | 13 | 22.2 |
UK and US ring sizes describe the same physical bands with different labels. Because every size maps to a real inside diameter in millimetres, the conversion between UK and US is exact, not an approximation. If you know the diameter of a ring that already fits, you can confirm both the UK and the US size from the millimetre column.
If your size sits between two rows, size up. It is easier to pad or resize a ring that is a touch loose than to stretch one that will not clear your knuckle. For a hands-on check, print the true-scale ring sizer and match a ring you own.
Common questions
How do I convert a UK ring size to US?
Find your UK size in the chart and read across to the US column, or use the converter above. Both point to the same physical band diameter, so the conversion is exact.
Is a UK ring size the same as US?
No, the labels differ, but the bands are the same physical sizes. The chart lines up each UK size with its US equivalent and the diameter in millimetres.
What if my size falls between two values?
Choose the larger size. A slightly loose ring can be resized or padded, but a ring that is too small will not pass the knuckle.
Last reviewed and updated on July 2, 2026. Conversion tables are checked against published international sizing standards.