Enter your finger circumference or inner diameter in mm to find your ring size in Korean, US, EU, UK, and Japanese standards.
Ring sizes may vary by brand and design. Always confirm fitting at a jewelry store before purchase.
| Korea (KR) | US | EU | UK | Japan (JP) | Inner Diameter (mm) | Circumference (mm) |
|---|---|---|---|---|---|---|
| 5 | 3 | 44 | F | 4 | 14 | 44 |
| 7 | 3.5 | 45.5 | G | 5 | 14.5 | 45.5 |
| 8 | 4 | 46.5 | H | 6 | 14.8 | 46.5 |
| 9 | 4.5 | 47.8 | I | 7 | 15.2 | 47.8 |
| 10 | 5 | 49 | J | 8 | 15.6 | 49 |
| 11 | 5.5 | 50.3 | K | 9 | 16 | 50.3 |
| 12 | 6 | 51.5 | L | 10 | 16.4 | 51.5 |
| 13 | 6.5 | 52.8 | M | 11 | 16.8 | 52.8 |
| 14 | 7 | 54 | N | 12 | 17.2 | 54 |
| 15 | 7.5 | 55.3 | O | 13 | 17.6 | 55.3 |
| 16 | 8 | 56.5 | P | 14 | 18 | 56.5 |
| 17 | 8.5 | 57.8 | Q | 15 | 18.4 | 57.8 |
| 18 | 9 | 59 | R | 16 | 18.8 | 59 |
| 19 | 9.5 | 60.3 | S | 17 | 19.2 | 60.3 |
| 20 | 10 | 61.5 | T | 18 | 19.6 | 61.5 |
| 21 | 10.5 | 62.8 | U | 19 | 20 | 62.8 |
| 22 | 11 | 64 | V | 20 | 20.4 | 64 |
| 23 | 11.5 | 65.3 | W | 21 | 20.8 | 65.3 |
| 24 | 12 | 66.5 | X | 22 | 21.2 | 66.5 |
| 25 | 12.5 | 67.8 | Y | 23 | 21.6 | 67.8 |
Wrap a thin string around your finger, mark it, then measure the length in mm to get your circumference.
Use a vernier caliper to measure the inner diameter of an existing ring.
Enter your measurement and click 'Find Size' to see all international ring sizes.
Wrap a thin string or strip of paper around your finger, mark where it meets, and measure the length in mm. This is your finger circumference. Measure in the evening or after eating when fingers may be slightly swollen for the most accurate fit.
Korea uses a number-based system ranging from size 5 to 25. Higher numbers indicate larger finger circumferences. The average for women is sizes 10–13, and for men sizes 15–20.
US sizing uses numbers, EU sizing uses numbers based on inner circumference in mm, and UK sizing uses letters. All systems represent the same physical ring size, just in different notation.
It is generally best to choose the larger size. A ring that is too tight can be difficult to put on and take off and may restrict blood circulation.
Getting the right ring size is essential when buying jewelry. Use this tool to compare Korean, US, EU, UK, and Japanese ring sizes side by side, and convert from inner diameter (mm) or circumference (mm) directly. Ideal for online shopping and international purchases to avoid costly sizing mistakes.