Japan Ring Size Chart

How the Japan ring sizing scale works

Japan uses a simple ascending numeric scale, typically running from around size 1 up to size 30, where the number climbs in step with the ring's inside circumference — there's no letters or half-sizes to navigate, just a straightforward number that gets larger as the ring does.

This same style of numeric scale, or something very close to it, is commonly used across other parts of Asia as well, though exact reference points can vary slightly by country and even by individual jeweler, so it's worth confirming locally for anything outside Japan itself.

Japan ring size chart

Each Japan size below is matched to its inside diameter, inside circumference, and closest US equivalent.

How to find your Japan ring size at home

1. Wrap a strip of string or paper around the base of the finger, mark where it overlaps, then measure that length against a ruler in millimeters.
2. Match the circumference to the closest value in the chart above.
3. Or measure the inside diameter of a ring that already fits and match it to the diameter column instead.

China and the rest of Asia

China's ring sizing commonly aligns closely with Japan's numeric scale, and it's widely used as a practical reference across the region, but it isn't universally identical everywhere — some retailers use their own local reference points. If you're buying from a jeweler outside Japan, it's worth double-checking which exact scale they mean by "size," especially for a purchase you can't easily resize.