Ring Size Calculator
Find your ring size in under a minute. Measure your finger with a strip of paper or string — or measure a ring you already own — and convert it instantly to US, UK and EU sizes.
Enter your measurement to see your size in US, UK and EU.
How to measure your ring size
- 1. Cut a thin strip of paper (or use a piece of string) about 10cm long.
- 2. Wrap it around the base of your finger — snug but not tight, just below the knuckle.
- 3. Mark the overlap point with a pen where the strip meets.
- 4. Measure the length in millimeters with a ruler — that’s your finger circumference.
- 5. Enter it in the calculator above to get your US, UK and EU ring sizes.
Tip: measure at the end of the day when fingers are largest, and if you land between sizes, choose the larger one.
Ring size conversion chart
| US size | UK size | EU size | Diameter (mm) | Circumference (mm) |
|---|---|---|---|---|
| 3 | F | 44 | 14.1 | 44.3 |
| 3.5 | G | 45.5 | 14.5 | 45.6 |
| 4 | H½ | 47 | 14.9 | 46.8 |
| 4.5 | I½ | 48 | 15.3 | 48.1 |
| 5 | J½ | 49 | 15.7 | 49.3 |
| 5.5 | K½ | 50.5 | 16.1 | 50.6 |
| 6 | L½ | 52 | 16.5 | 51.8 |
| 6.5 | M½ | 53 | 16.9 | 53.1 |
| 7 | N½ | 54.5 | 17.3 | 54.3 |
| 7.5 | O½ | 55.5 | 17.7 | 55.6 |
| 8 | P½ | 57 | 18.1 | 56.9 |
| 8.5 | Q½ | 58 | 18.5 | 58.1 |
| 9 | R½ | 59.5 | 18.9 | 59.4 |
| 9.5 | S½ | 61 | 19.4 | 60.9 |
| 10 | T½ | 62 | 19.8 | 62.2 |
| 10.5 | U½ | 63.5 | 20.2 | 63.5 |
| 11 | V½ | 64.5 | 20.6 | 64.7 |
| 11.5 | W½ | 66 | 21.0 | 66.0 |
| 12 | X½ | 67 | 21.4 | 67.2 |
| 12.5 | Z | 68.5 | 21.8 | 68.5 |
| 13 | Z+1 | 69.5 | 22.2 | 69.7 |
Found your size?
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Shop jewelryRing sizing FAQs
How do I measure my ring size at home?+
Wrap a thin strip of paper or a piece of string snugly around the base of your finger, mark where it overlaps, and measure that length in millimeters with a ruler — that's your finger circumference. Enter it in the calculator above to get your US, UK and EU sizes.
What time of day should I measure my finger?+
At the end of the day, when your fingers are at their largest. Fingers are smaller in the morning and in cold weather, so an evening measurement at normal room temperature gives the most reliable fit.
What if I'm between two ring sizes?+
Choose the larger size. A slightly loose ring can be worn comfortably (or resized down more easily), while a tight ring can be uncomfortable and hard to remove.
Can I measure using a ring I already own?+
Yes — measure the inside diameter of a ring that fits the intended finger, straight across the widest inner point, in millimeters. Switch the calculator to "ring diameter" mode and enter that number.
Do wide bands fit differently?+
Wide bands (6mm+) fit more snugly than thin ones. If you're buying a wide band and measure between sizes, go up a half size for comfort.
Are US, UK and EU ring sizes different?+
Yes. US sizes use numbers (3–13), UK sizes use letters (F–Z), and EU/ISO sizes are the finger circumference in millimeters. The calculator and chart on this page convert between all three.