Japan to US ring size converter
Japanese (JIS) sizes are numeric but based on the inner diameter in millimetres, so they climb faster than US numbers. A Japan 12 is about a US 6 and a Japan 14 is about a US 7. China and South Korea commonly use the same scale. Enter a Japan size below.
Quick answer
A Japan 14 is 7 in US (about 54.4 mm inner circumference). Use the converter for your exact size, or the chart below for the full range.
Between two sizes? Size up for a comfortable fit, see how to measure accurately.
Japan → US at a glance
- 7 = 4
- 9 = 5
- 11 = 6
- 14 = 7
- 16 = 8
- 19 = 9
- 21 = 10
- 24 = 11
Japan to US ring size chart
| JPJapan | USUS / Canada | mmCircumference | mmDiameter |
|---|---|---|---|
| 7 | 4 | 46.7 | 14.9 |
| 8 | 4½ | 48.0 | 15.3 |
| 9 | 5 | 49.3 | 15.7 |
| 10 | 5½ | 50.5 | 16.1 |
| 11 | 6 | 51.8 | 16.5 |
| 13 | 6½ | 53.1 | 16.9 |
| 14 | 7 | 54.4 | 17.3 |
| 15 | 7½ | 55.6 | 17.7 |
| 16 | 8 | 56.9 | 18.1 |
| 18 | 8½ | 58.2 | 18.5 |
| 19 | 9 | 59.5 | 18.9 |
| 20 | 9½ | 60.7 | 19.3 |
| 21 | 10 | 62.0 | 19.7 |
| 22 | 10½ | 63.3 | 20.1 |
| 24 | 11 | 64.6 | 20.5 |
| 25 | 11½ | 65.8 | 21.0 |
| 26 | 12 | 67.1 | 21.4 |
Common questions
How do I convert a Japan ring size to US?
Enter your Japan size in the converter above and read the US result, or find your row in the chart below. Every value is calculated from the ring’s inner circumference, so it works in both directions.
What is a Japan 14 in US?
A Japan 14 is 7 in US. That ring has an inner circumference of about 54.4 mm.
Related conversions
Or see the full ring size chart.