Ring Size Calculator
Measure round your finger with a strip of paper, or measure the inside of a ring that already fits. Enter the number and what it is, and the calculator gives your US, UK and EU sizes.
- Finger or ring
- US, UK and EU
- Wide band advice
Wrap a paper strip round the base of the finger, mark where it overlaps and measure it flat in millimetres.
Ring sizes are just a way of naming one number, the inside size of the ring. The EU and ISO size is the inside circumference in millimetres. US sizes go up by about 0.8 mm of diameter a size, and UK sizes use letters from A to Z.
Ring size chart
US, UK and EU. Search for a size.
| US | UK | EU (ISO) | Diameter (mm) | Circumference (mm) |
|---|---|---|---|---|
| 4 | H | 47 | 14.9 | 46.8 |
| 5 | J½ | 50 | 15.7 | 49.3 |
| 6 | L½ | 52 | 16.5 | 51.9 |
| 7 | N½ | 55 | 17.3 | 54.4 |
| 8 | P½ | 57 | 18.1 | 57 |
| 9 | R½ | 60 | 19 | 59.5 |
| 10 | T½ | 62 | 19.8 | 62.1 |
| 11 | V½ | 65 | 20.6 | 64.6 |
| 12 | Y | 67 | 21.4 | 67.2 |
Sizes between brands can differ by half a size. Try a ring on if you can.
US size and ring diameter
Drawn to scale. Slide the US size.
The ring is drawn at about seven times life size. The hole is the inside diameter that fits your finger.
How to measure your ring size
Paper strip method. Step through it.
Cut a strip
Paper or string.
Measure two or three times. Fingers swell in the heat and shrink in the cold, so measure at a normal room temperature.
Thin, wide or comfort fit
Band styles. Compare them.
Under about 4 mm wide.
Over about 6 mm wide.
Rounded inside.
Comfort fit bands are rounded inside and slide over the knuckle more easily, so some people go down a quarter size.
Before you order
Get it right first time. Tick each item.
Tick each item as you go.
If your knuckle is much larger than the base of your finger, size for the knuckle so the ring can go on.
What you get
Every ring size. Each tile explains one result.
Quarter sizes.
Letters A to Z.
Circumference.
Inside, in mm.
Size advice.
Many rings can be resized one or two sizes, but some, like eternity bands, cannot.
Frequently Asked Questions
No question matches that search.
How do I find my ring size at home?
Wrap a strip of paper round your finger, mark the overlap and measure it in millimetres. Enter that circumference here.
How do I measure a ring I already own?
Measure straight across the inside of the ring in millimetres and choose ring inside diameter.
What is the most common ring size?
For women about US 6 to 7, and for men about US 9 to 10.
Should a wide band be a bigger size?
Yes, usually half a size larger, because a wide band grips more of the finger.
What is the difference between US and UK ring sizes?
US sizes use numbers and UK sizes use letters. Both describe the same inside measurement.
What if I am between two sizes?
Choose the larger one, especially for a wide band.
Does my ring size change during the day?
Yes. Fingers are smaller in the morning and in the cold, and larger in the evening and the heat.
A ring that fits first time
Measure your finger or an old ring and get your size in every system. Then choose half a size up for a wide band.
More size calculators
Each one has its own calculator, worked examples and answers to common questions.