Measure twice
Ring size, without a guessing game.
UK letters, with approximate US and EU figures and the inner circumference in millimetres. We still measure at the bench before a band is made.
Conversion table
| UK | Circumference | Diameter | US | EU |
|---|---|---|---|---|
| F | 44.2 mm | 14.1 mm | 3 | 44 |
| G | 45.5 mm | 14.5 mm | 3.5 | 45.5 |
| H | 46.8 mm | 14.9 mm | 4 | 47 |
| I | 48.0 mm | 15.3 mm | 4.5 | 48 |
| J | 49.3 mm | 15.7 mm | 5 | 49 |
| K | 50.6 mm | 16.1 mm | 5.5 | 50.5 |
| L | 51.9 mm | 16.5 mm | 6 | 52 |
| M | 53.1 mm | 16.9 mm | 6.5 | 53 |
| N | 54.4 mm | 17.3 mm | 7 | 54 |
| O | 55.7 mm | 17.7 mm | 7.5 | 55.5 |
| P | 57.0 mm | 18.1 mm | 8 | 57 |
| Q | 58.3 mm | 18.5 mm | 8.5 | 58 |
| R | 59.5 mm | 18.9 mm | 9 | 59 |
| S | 60.8 mm | 19.4 mm | 9.5 | 61 |
| T | 62.1 mm | 19.8 mm | 10 | 62 |
| U | 63.5 mm | 20.2 mm | 10.5 | 63 |
| V | 64.6 mm | 20.6 mm | 11 | 64.5 |
| W | 65.9 mm | 21.0 mm | 11.5 | 66 |
| X | 67.2 mm | 21.4 mm | 12 | 67 |
| Y | 68.5 mm | 21.8 mm | 12.5 | 68.5 |
| Z | 69.7 mm | 22.2 mm | 13 | 69.5 |
Half sizes sit roughly halfway between letters. These conversions are approximate sample figures. We measure a finger, or a ring you already wear, before making anything.
Calculator
Use a strip of paper or a piece of string for the circumference, or measure the inside of a ring that already fits for the diameter. Enter millimetres.
The calculator needs JavaScript. The table beside it works without.
How to measure at home
With a strip of paper
Cut a strip about 8 cm long and 4 mm wide. Wrap it around the finger, snug but not tight, and mark where it overlaps. Lay it flat and measure the mark in millimetres. That number is the circumference. Fingers are slightly larger at the end of the day, and smaller when they are cold.
With a ring you already wear
Choose a ring that fits the same finger. Measure the inside diameter in millimetres, straight across the middle, not including the metal. If you can only measure the outside, do not guess. Bring the ring in.
Knuckles and wide bands
If the knuckle is larger than the base of the finger, measure both and tell us. A wider band needs a little more room than a thin one. The slim court band and a signet will not always share a letter.
When a home measurement is not enough
Book a ring sizing visit. We use a set of mandrels and, if you have one, the ring you already trust. The chart on this page is a sample conversion, not a promise that a letter will fit.
Printable check
Print at 100% scale. Do not choose “fit to page”. The bar should measure 20 mm on a ruler. Then lay a ring you already wear on the circle that matches its inner edge. On screen these circles are only a guide; paper and printer settings change the size.