Ring size

Ring size 12.5: US 12.5 in mm, UK, EU and Japan

A US size 12.5 ring has an inside diameter of 21.8 mm and an inside circumference of 68.5 mm. The same ring is a Y½ in the UK and Australia, a 68.5 on the EU/ISO scale and a 27 in Japan and Korea. The figures below come from the same geometry as the full chart, so they agree with it to a tenth of a millimeter.

US 12.5 in every sizing system

US 12.5 with the half size below and above it, so a measurement that lands between two sizes still has a row to read.
US / Canada	UK / Australia	EU / ISO (circumference, mm)	Japan / Korea	Inside diameter (mm)
US 12	X½	67.2	26	21.4
US 12.5This size	Y½	68.5	27	21.8
US 13	Z½	69.7	29	22.2

What a size 12.5 ring measures

Inside diameter 21.8 mm (about 0.86 in), inside circumference 68.5 mm. Measuring a ring that already fits? Measure the inside edge to edge for the diameter. Measuring a finger? Wrap a strip of paper around its base and compare the overlap with the circumference.

Is US 12.5 a common ring size?

US 12.5 is above the 8 to 12 range most men's bands are stocked in. Jewelers can make most designs to order; allow extra time and ask whether the band width changes the fit.

Between two sizes?

Take the larger one. A ring is easier to make smaller than larger, a wide band needs a little more room than a thin one, and fingers swell in heat and in the evening. A jeweler's sizer set settles it in a minute.

Convert a measurement to a ring size

Measure a ring that already fits the right finger, or the finger itself, and enter the number in millimeters.

Quick answers

Frequently asked questions

What is a US ring size 12.5 in mm?

US 12.5 is 21.8 mm across the inside and 68.5 mm around the inside. The millimeter circumference is also the EU/ISO size, 68.5.

What is US 12.5 in UK ring sizes?

US 12.5 is a UK and Australian Y½. UK letters step 1.25 mm of circumference at a time, so a half letter is a real difference.

What is US 12.5 in EU ring sizes?

US 12.5 is EU/ISO 68.5. The EU number is the inside circumference in millimeters, so a shop that stocks whole sizes will offer the nearest one.

What is US 12.5 in Japanese and Korean ring sizes?

US 12.5 is a Japanese and Korean 27. Those scales step a third of a millimeter of diameter per number, so they are finer than US half sizes.

Every ring size, US 3 to 13

Conversions are rounded to the nearest standard size, and published charts differ from each other by up to half a size. Treat the result as a close estimate, confirm it with a jeweler's sizer before buying, and check the resizing policy.