UK Ring Size Chart
The UK ring sizing system uses letters from A to Z (and beyond for very large sizes). This is the standard used by British jewellers and is based on the inner circumference of the ring. This reference chart gives you every UK letter size with the corresponding diameter, circumference, and US and EU equivalents — essential for jewellery making and online ring shopping.
Full UK Ring Size Table
| UK Size | Diameter (mm) | Circumference (mm) | US Size | EU Size |
|---|---|---|---|---|
| A | 12.04 | 37.8 | ½ | — |
| B | 12.45 | 39.1 | 1 | — |
| C | 12.85 | 40.4 | 1½ | 40.5 |
| D | 13.26 | 41.7 | 2 | 41.5 |
| E | 13.67 | 42.9 | 2½ | 43 |
| F | 14.07 | 44.2 | 3 | 44 |
| G | 14.48 | 45.5 | 3½ | 45.5 |
| H | 14.88 | 46.8 | 4 | 47 |
| I | 15.29 | 48.0 | 4½ | 48 |
| J | 15.49 | 48.7 | 5 | 49 |
| K | 15.90 | 49.9 | 5½ | 50 |
| L | 16.31 | 51.2 | 6 | 51 |
| M | 16.71 | 52.5 | 6¼ | 52.5 |
| N | 17.12 | 53.8 | 7 | 54 |
| O | 17.53 | 55.1 | 7½ | 55 |
| P | 17.93 | 56.3 | 8 | 56 |
| Q | 18.34 | 57.6 | 8½ | 57.5 |
| R | 18.75 | 58.9 | 9 | 59 |
| S | 19.15 | 60.2 | 9½ | 60 |
| T | 19.56 | 61.4 | 10 | 61.5 |
| U | 19.96 | 62.7 | 10½ | 63 |
| V | 20.37 | 64.0 | 11 | 64 |
| W | 20.78 | 65.3 | 11½ | 65 |
| X | 21.18 | 66.6 | 12 | 66.5 |
| Y | 21.59 | 67.8 | 12½ | 68 |
| Z | 21.79 | 68.5 | 13 | 68.5 |
EU sizes correspond to the inner circumference in mm (rounded). US and EU equivalents are approximate as systems don't map exactly.
How to Measure Ring Size
The most accurate method is to use a ring mandrel (a tapered metal or plastic rod with size markings). Slide an existing ring that fits well onto the mandrel and read the size. Alternatively, wrap a strip of paper or string snugly around the finger, mark where it overlaps, and measure the length in mm to get the circumference. Match this to the table above.
Tips: Measure at the end of the day when fingers are slightly larger. Avoid measuring when hands are cold (fingers shrink). Wide bands (6 mm+) typically need to be a half to one size larger for comfort.
Calculate Ring Dimensions
Use our ring size calculator for instant conversions and metal weight calculations:
- Ring Size Calculator — convert between UK, US, and EU ring sizes, plus calculate the metal needed for your ring
UK ring sizes follow the British Standard (BS 6820). Individual finger sizes can vary by up to half a size between morning and evening, and seasonally. For expensive rings, always verify sizing with a professional jeweller's ring gauge.