Ring Size Converter
Choose your ring size in any system. You can also match an existing ring by its inside diameter.
Ring sizes chart
| UK / AU | US / CA | Diameter (mm) | Circumference (mm) | EU / ISO |
|---|---|---|---|---|
| A½ | ½ | 12.0 | 37.8 | 38 |
| B | ¾ | 12.2 | 38.5 | 38 |
| B½ | 1 | 12.4 | 39.1 | 39 |
| C | 1¼ | 12.6 | 39.7 | 40 |
| C½ | 1½ | 12.8 | 40.4 | 40 |
| D | 1¾ | 13.1 | 41.0 | 41 |
| D½ | 2 | 13.3 | 41.6 | 42 |
| E | 2¼ | 13.5 | 42.3 | 42 |
| E½ | 2½ | 13.7 | 42.9 | 43 |
| F | 2¾ | 13.9 | 43.6 | 44 |
| F½ | 3 | 14.1 | 44.2 | 44 |
| G | 3¼ | 14.3 | 44.8 | 45 |
| G½ | 3½ | 14.5 | 45.5 | 45 |
| H | 3¾ | 14.7 | 46.1 | 46 |
| H½ | 4 | 14.9 | 46.8 | 47 |
| I | 4¼ | 15.1 | 47.4 | 47 |
| I½ | 4½ | 15.3 | 48.0 | 48 |
| J | 4¾ | 15.5 | 48.7 | 49 |
| J½ | 5 | 15.7 | 49.3 | 49 |
| K | 5¼ | 15.9 | 49.9 | 50 |
| K½ | 5½ | 16.1 | 50.6 | 51 |
| L | 5¾ | 16.3 | 51.2 | 51 |
| L½ | 6 | 16.5 | 51.9 | 52 |
| M | 6¼ | 16.7 | 52.5 | 52 |
| M½ | 6½ | 16.9 | 53.1 | 53 |
| N | 6¾ | 17.1 | 53.8 | 54 |
| N½ | 7 | 17.3 | 54.4 | 54 |
| O | 7¼ | 17.5 | 55.0 | 55 |
| O½ | 7½ | 17.7 | 55.7 | 56 |
| P | 7¾ | 17.9 | 56.3 | 56 |
| P½ | 8 | 18.1 | 57.0 | 57 |
| Q | 8¼ | 18.3 | 57.6 | 58 |
| Q½ | 8½ | 18.5 | 58.2 | 58 |
| R | 8¾ | 18.7 | 58.9 | 59 |
| R½ | 9 | 18.9 | 59.5 | 60 |
| S | 9¼ | 19.1 | 60.2 | 60 |
| S½ | 9½ | 19.4 | 60.8 | 61 |
| T | 9¾ | 19.6 | 61.4 | 61 |
| T½ | 10 | 19.8 | 62.1 | 62 |
| U | 10¼ | 20.0 | 62.7 | 63 |
| U½ | 10½ | 20.2 | 63.3 | 63 |
| V | 10¾ | 20.4 | 64.0 | 64 |
| V½ | 11 | 20.6 | 64.6 | 65 |
| W | 11¼ | 20.8 | 65.3 | 65 |
| W½ | 11½ | 21.0 | 65.9 | 66 |
| X | 11¾ | 21.2 | 66.5 | 67 |
| X½ | 12 | 21.4 | 67.2 | 67 |
| Y | 12¼ | 21.6 | 67.8 | 68 |
| Y½ | 12½ | 21.8 | 68.5 | 68 |
| Z | 12¾ | 22.0 | 69.1 | 69 |
| Z½ | 13 | 22.2 | 69.7 | 70 |
How to find your ring size at home
From a ring that fits: measure the inside diameter across the middle in millimetres and choose it in the "Diameter" system above.
From your finger: wrap a strip of paper around the base of your finger, mark where it overlaps, and measure the length in millimetres. That is your circumference, which is the European (ISO) size.
Fingers swell when warm and in the evening, so measure at room temperature. If the ring has a wide band (over 6 mm), go up half a size.
Ring size pages
Look up a single size to see its exact equivalents in other countries:
UK sizes: UK ring size B · UK ring size C · UK ring size D · UK ring size E · UK ring size F · UK ring size G · UK ring size H · UK ring size I · UK ring size J · UK ring size K · UK ring size L · UK ring size M · UK ring size N · UK ring size O · UK ring size P · UK ring size Q · UK ring size R · UK ring size S · UK ring size T · UK ring size U · UK ring size V · UK ring size W · UK ring size X · UK ring size Y · UK ring size Z
Frequently asked questions
What is a UK N ring in US size?
A UK N is a US 6.75, with an inside diameter of about 17.1 mm.
What is the most common ring size?
For women in the UK it is around L to N (US 6 to 7). For men it is around T (US 9.75).
What EU ring size is a US 7?
A US 7 ring has a circumference of about 54.4 mm, so it is an EU 54.