Ring Size Conversion Chart

How to use this chart

1. Start from a size you already know. That can be a US number, a UK letter, a European or Japanese number, or a measurement in millimeters taken from a ring that fits.
2. Find it in the chart. Type it into the search box at the top of the table, or scroll to the matching row.
3. Read across the row. Every column in that row describes the same ring, so you can move between systems in either direction.

The most common ring sizes

If you are buying a surprise gift and have nothing to measure, these are the sizes to fall back on. They are a starting point, not a substitute for measuring.

Hand size varies far more than these averages suggest, so treat them as a last resort. If the ring is a surprise, borrowing a ring they already wear on the correct finger is much more reliable, measure its inside diameter and find that measurement in the chart above.

Measuring at home in millimetres

You do not need a sizer to use this chart. Either measurement will find your row:

• From a ring that fits: measure the inside diameter straight across the middle, in millimetres. A ring measuring 16.5 mm inside is a US 6.
• From your finger: wrap a strip of paper or a length of string snugly around the base of the finger, mark where it overlaps, and measure the length. That is your inside circumference, 51.8 mm for a US 6.
• Check the knuckle. The ring has to pass it. If your knuckle is noticeably wider than the base of your finger, measure both and choose a size between them.

Why ring sizes differ between countries

The three main systems measure the same ring in three different ways, which is why there is no formula to convert between them and why a chart is necessary.

The one measurement that is universal is the inside diameter or circumference in millimetres. If you are ever unsure which system a size refers to, ask for the millimetres.

Six things that change the size you need

Ring size questions

What is the most common ring size for women?

US size 6 to 7 is the most common range for women, with 6½ the single most requested size. That corresponds to roughly UK L½ to N½, and an inside circumference of 51.8 to 54.4 mm.

What is the most common ring size for men?

US size 9 to 10 is the most common range for men, with 10 the single most requested size. That corresponds to roughly UK R½ to T½, and an inside circumference of 59.5 to 62.1 mm.

How do I convert my UK ring size to US?

Find your UK letter size in the chart above and read across to the US column. UK sizes run alphabetically and US sizes numerically, so there is no formula — you need the conversion table. As a reference point, UK L½ is US 6 and UK T½ is US 10.

How do I find my ring size in millimeters?

Measure the inside diameter of a ring that already fits, straight across the middle, or wrap a strip of paper around your finger and measure its length to get the circumference. Find that measurement in the first columns of the chart above and read across to your size.

Are European ring sizes the same as the circumference?

Broadly, yes. Most European sizing follows the ISO standard, where the size number is based on the inside circumference of the ring in millimeters. That is why European sizes appear as numbers in the fifties and sixties rather than as small numbers or letters.

How do Japanese ring sizes convert to US sizes?

Japanese sizes run from 1 to about 27 in whole-number steps. As reference points, Japan 12 is US 6, Japan 14 is US 7, and Japan 21 is US 10. Find the Japan column in the chart above and read across the row for the exact conversion.

Does the width of a ring change the size I need?

Yes. A wide band covers more of your finger and fits more tightly, so bands of about 6 mm or wider usually need a half size larger than a narrow band. If you are choosing a wide ring, size it in the width you actually intend to buy.

What if I am between two ring sizes?

Go up to the larger size, particularly for a wide band or if you have prominent knuckles. A ring that is slightly loose can be made smaller far more easily than a ring that will not pass the knuckle can be worn at all.

Can a ring be resized after I buy it?

Most plain and lightly set gold and platinum rings can be resized. Eternity bands set all the way around, and rings with a pattern running the full circumference, often cannot. At 25karats, resizing is done in-house and most designs can be adjusted up or down one size free within 60 days.

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