Guide
Find your ring size
UK, US and EU sizing made simple.
A ring should sit comfortably at the base of the finger and offer a small resistance when slipped over the knuckle. Too loose and it spins, too tight and it gets stuck. Here are three ways to measure accurately at home.
Method 1: Order our complimentary sizer
We post a precision plastic ring-sizer free of charge anywhere in the UK (2-3 business days). Slip it on, lock the size and you have an exact UK letter reading. Email info@buyfinediamonds.comwith your delivery address and we'll send one out.
Method 2: Measure a ring you already own
- Choose a ring that fits the intended finger well. Place it on a flat surface.
- Measure the inside diameter (edge to edge) in millimetres. Use a digital ruler if you have one for higher accuracy.
- Match the inside diameter against the chart below, or convert to circumference by multiplying the inside diameter by π (3.14159).
Method 3: Measure your finger directly
- Wrap a length of string or a strip of paper around the base of the finger.
- Mark where the strip overlaps with a pen.
- Measure the marked length in millimetres. Match the circumference in the chart.
Size chart
| UK | US | Inside circumference |
|---|---|---|
| F | 3 | 44.1 mm |
| G | 3 ½ | 45.2 mm |
| H | 4 | 46.5 mm |
| I | 4 ½ | 47.7 mm |
| J | 5 | 48.7 mm |
| K | 5 ¼ | 49.9 mm |
| L | 5 ¾ | 51.2 mm |
| M | 6 ¼ | 52.5 mm |
| N | 6 ½ | 53.7 mm |
| O | 7 | 55.0 mm |
| P | 7 ½ | 56.2 mm |
| Q | 8 | 57.5 mm |
| R | 8 ½ | 58.7 mm |
| S | 9 | 60.0 mm |
| T | 9 ½ | 61.3 mm |
| U | 10 | 62.5 mm |
| V | 10 ½ | 63.8 mm |
| W | 11 | 65.1 mm |
| X | 11 ½ | 66.4 mm |
| Y | 12 | 67.6 mm |
| Z | 12 ½ | 68.9 mm |
Tips that catch most people out
- Measure at the end of the day when your fingers are at their largest.
- Avoid measuring after exercise, on a hot day, after a salty meal or after alcohol - fingers swell.
- A wide band (3mm+) tends to fit a touch tighter than a thin band. If you're buying a wide eternity ring, consider going half a size up.
- Knuckle wider than the base? Measure both, then pick a size you can pass the knuckle with but that still sits snug at the base.
Resizing
We offer free resizing within 12 months of purchase on most pieces. Full eternity rings, and rings with channel-set or pavé stones near the shank, may not be resizable. We'll always tell you up-front at purchase.