Ring size chart
A US size 7 ring has an inside diameter of about 17.3 mm and an inside circumference of 54.4 mm (EU size 54). Enter what you know to find your size in every system, for men's and women's rings alike.
Ring size chart: the tool
Find your ring size
No ring at hand? Wrap a strip of paper round the finger, mark where it meets, and measure the strip in mm: that is the circumference.
Actual size
Lay one of your rings on the circle: the inside edge should sit on the line.
How to measure
Ring sizes chart: US, UK, EU and Japan (men and women)
| US / Canada | Inside diameter | Diameter (in) | Circumference (ISO, EU) | UK / Australia | Japan / China | Italy / Spain / Switzerland |
|---|---|---|---|---|---|---|
| 3 | 14.07 mm | 0.554 in | 44.2 mm | F | 4 | 4.2 |
| 3.25 | 14.27 mm | 0.562 in | 44.8 mm | F 1/2 | 5 | 4.8 |
| 3.5 | 14.48 mm | 0.57 in | 45.5 mm | G | n/a | 5.5 |
| 3.75 | 14.68 mm | 0.578 in | 46.1 mm | G 1/2 | 6 | 6.1 |
| 4 | 14.88 mm | 0.586 in | 46.8 mm | H | 7 | 6.8 |
| 4.25 | 15.09 mm | 0.594 in | 47.4 mm | H 1/2 | n/a | 7.4 |
| 4.5 | 15.29 mm | 0.602 in | 48 mm | I | 8 | 8 |
| 4.75 | 15.49 mm | 0.61 in | 48.7 mm | J | n/a | 8.7 |
| 5 | 15.7 mm | 0.618 in | 49.3 mm | J 1/2 | 9 | 9.3 |
| 5.25 | 15.9 mm | 0.626 in | 50 mm | K | n/a | 10 |
| 5.5 | 16.1 mm | 0.634 in | 50.6 mm | K 1/2 | 10 | 10.6 |
| 5.75 | 16.31 mm | 0.642 in | 51.2 mm | L | n/a | 11.2 |
| 6 | 16.51 mm | 0.65 in | 51.9 mm | L 1/2 | 11 | 11.9 |
| 6.25 | 16.71 mm | 0.658 in | 52.5 mm | M | 12 | 12.5 |
| 6.5 | 16.92 mm | 0.666 in | 53.1 mm | M 1/2 | 13 | 13.1 |
| 6.75 | 17.12 mm | 0.674 in | 53.8 mm | N | n/a | 13.8 |
| 7 | 17.32 mm | 0.682 in | 54.4 mm | N 1/2 | 14 | 14.4 |
| 7.25 | 17.53 mm | 0.69 in | 55.1 mm | O | n/a | 15.1 |
| 7.5 | 17.73 mm | 0.698 in | 55.7 mm | O 1/2 | 15 | 15.7 |
| 7.75 | 17.93 mm | 0.706 in | 56.3 mm | P | n/a | 16.3 |
| 8 | 18.14 mm | 0.714 in | 57 mm | P 1/2 | 16 | 17 |
| 8.25 | 18.34 mm | 0.722 in | 57.6 mm | P 3/4 | n/a | 17.6 |
| 8.5 | 18.54 mm | 0.73 in | 58.3 mm | Q 1/4 | 17 | 18.3 |
| 8.75 | 18.75 mm | 0.738 in | 58.9 mm | R | n/a | 18.9 |
| 9 | 18.95 mm | 0.746 in | 59.5 mm | R 1/2 | 18 | 19.5 |
| 9.25 | 19.15 mm | 0.754 in | 60.2 mm | S | n/a | 20.2 |
| 9.5 | 19.35 mm | 0.762 in | 60.8 mm | S 1/2 | 19 | 20.8 |
| 9.75 | 19.56 mm | 0.77 in | 61.4 mm | T | n/a | 21.4 |
| 10 | 19.76 mm | 0.778 in | 62.1 mm | T 1/2 | 20 | 22.1 |
| 10.25 | 19.96 mm | 0.786 in | 62.7 mm | U | 21 | 22.7 |
| 10.5 | 20.17 mm | 0.794 in | 63.4 mm | U 1/2 | 22 | 23.4 |
| 10.75 | 20.37 mm | 0.802 in | 64 mm | V | n/a | 24 |
| 11 | 20.57 mm | 0.81 in | 64.6 mm | V 1/2 | 23 | 24.6 |
| 11.25 | 20.78 mm | 0.818 in | 65.3 mm | W | n/a | 25.3 |
| 11.5 | 20.98 mm | 0.826 in | 65.9 mm | W 1/2 | 24 | 25.9 |
| 11.75 | 21.18 mm | 0.834 in | 66.6 mm | X | n/a | 26.6 |
| 12 | 21.39 mm | 0.842 in | 67.2 mm | X 1/2 | 25 | 27.2 |
| 12.25 | 21.59 mm | 0.85 in | 67.8 mm | Y | n/a | 27.8 |
| 12.5 | 21.79 mm | 0.858 in | 68.5 mm | Y 1/2 | 26 | 28.5 |
| 12.75 | 22 mm | 0.866 in | 69.1 mm | Z | n/a | 29.1 |
| 13 | 22.2 mm | 0.874 in | 69.7 mm | Z 1/2 | 27 | 29.7 |
| 13.25 | 22.4 mm | 0.882 in | 70.4 mm | Z1 | n/a | 30.4 |
| 13.5 | 22.61 mm | 0.89 in | 71 mm | n/a | n/a | 31 |
How ring size systems work
- ISO 8653:2016 defines ring size as the inner circumference in mm (continental Europe).
- US/Canada sizes step by 0.032 in (0.8128 mm) of inner diameter per whole size, in quarter sizes.
- UK/Ireland/Australia use letters with half sizes; BS 6820:1987 sets one letter = 1.25 mm of circumference, with C = 40 mm.
- The main table is the Wikipedia equivalency table, which is built from inch diameters and flagged on Wikipedia as possible original research. Angara's retailer chart is kept as a cross check.
Printable ring sizer
Print this section at 100% scale (turn off "fit to page"), then check the line below with a ruler: it must measure exactly 100 mm. If it does, lay a ring that fits on the circles; the right size is the circle whose edge sits just inside the ring.
14.88 mm
15.7 mm
16.51 mm
17.32 mm
18.14 mm
18.95 mm
19.76 mm
20.57 mm
21.39 mm
22.2 mm
Related tools
This chart only works at 100%. How to print at actual size.
Questions
How do I find my ring size at home?
Measure the inside diameter of a ring that fits in millimeters and enter it above, or wrap a paper strip round the finger, measure it in mm and enter that as the circumference. You can also print the sizer on this page.
What is the most common ring size?
We have not found a published, sourced survey of ring sizes, so we do not quote one.
What size is 17 mm inside diameter?
About US 6.5 (16.92 mm), UK M 1/2, EU (ISO) 53. Enter any diameter above to see the closest sizes.
Are UK and US ring sizes the same?
No. The US uses numbers in quarter steps and the UK and Australia use letters. US 7 is UK N 1/2 in the table above.
Sources
- Wikipedia: Ring size (checked 2026-10-02)
- Angara: Ring Size Chart: US, UK & International Sizes (checked 2026-10-02)
- onemall (blog): Japanese Ring Size to US: Full Conversion Chart in mm (checked 2026-10-02)
Last checked: 5 October 2026