This guide covers two ways to measure at home, a full Japanese ring size (号) chart, and a few tips for choosing the right fit. Some variation in fit is unavoidable from one design to the next, but we hope it helps you find the size closest to the fit you're after.
The String Method
A quick measurement with materials you already have.
- Cut a piece of string, thread, or a narrow strip of paper about 15cm long.
- Wrap it around the base of the finger you're sizing for, snug enough to slip off without force.
- Mark or pinch the string where it overlaps to form a complete circle.
- Lay the string flat and measure from one end to the mark in millimeters. This is your finger's circumference.
- Find your Japanese ring size (号) in the chart below.
The Paper Strip Method
Paper holds its shape better than thread, so it's more accurate.
- Cut a strip of paper about 6mm wide and 10cm long.
- Wrap it around the base of your finger and check that it clears your knuckle. A ring that won't pass the knuckle can't be worn.
- Mark where the paper overlaps.
- Flatten it and measure with a ruler in millimeters.
03Japanese Ring Size (号) Chart
| Japan Size (号) | Circumference (mm) | Inner Diameter (mm) |
|---|---|---|
| 1号 | 40.8 | 13.0 |
| 2号 | 41.9 | 13.3 |
| 3号 | 42.9 | 13.7 |
| 4号 | 44.0 | 14.0 |
| 5号 | 45.0 | 14.3 |
| 6号 | 46.1 | 14.7 |
| 7号 | 47.1 | 15.0 |
| 8号 | 48.2 | 15.3 |
| 9号 | 49.2 | 15.7 |
| 10号 | 50.3 | 16.0 |
| 11号 | 51.3 | 16.3 |
| 12号 | 52.4 | 16.7 |
| 13号 | 53.4 | 17.0 |
| 14号 | 54.5 | 17.3 |
| 15号 | 55.5 | 17.7 |
| 16号 | 56.5 | 18.0 |
| 17号 | 57.6 | 18.3 |
| 18号 | 58.6 | 18.7 |
| 19号 | 59.7 | 19.0 |
| 20号 | 60.7 | 19.3 |
| 21号 | 61.8 | 19.7 |
| 22号 | 62.8 | 20.0 |
| 23号 | 63.9 | 20.3 |
| 24号 | 64.9 | 20.7 |
| 25号 | 66.0 | 21.0 |
| 26号 | 67.0 | 21.3 |
| 27号 | 68.1 | 21.7 |
| 28号 | 69.1 | 22.0 |
| 29号 | 70.2 | 22.3 |
| 30号 | 71.2 | 22.7 |
04Tips for Getting It Right
Timing matters
Fingers are larger in the evening than the morning, and larger when warm than cold. Measure in the afternoon or evening for everyday wear, or once your hands have warmed up if they tend to run cold.
Account for the knuckle
If your knuckle is larger than the base of your finger, size for the knuckle. A ring adjuster can take up the extra space at the base.
Wide bands fit tighter
A wide band over about 6mm feels tighter than a slim band at the same size. Go up half a size for wide rings.
Measure twice
Use both methods and take the average. Measure the same finger two or three times and use the most consistent result.
What to Do If You're Between Sizes
If your circumference falls between two sizes, consider which finger the ring is for and how you like it to fit. Index fingers are usually worn a little looser; middle fingers and pinkies stay put better snug.
When in doubt, go up half a size. A slightly loose ring can be adjusted; one that won't go on can't.
Contacting Us
If you're unsure about sizing for a specific piece, reach out before purchasing.
contact@mrsupply.store