In France and Germany this ring is written 46, because both national systems label a band by its inner circumference in millimetres, the same number ISO uses.
UK to US conversion
Reading UK letters into US numbers reverses that alphabet: UK L is US 6, UK N is US 7, UK Q is US 8.5, one letter for every half a US size. Past UK Z the scale runs out of letters and switches to Z1 and Z2, which answer US 13.5 and 14. Since one letter can land on a US whole or half, a UK buyer converting to US should confirm the half, especially before ordering a size that cannot be adjusted after casting.
At this size, UK to US
One size up from UK G, US moves 0.5 to US 4 while UK steps to UK H. This size runs a 14.5 mm bore. For UK G, the US column here runs US 3, US 3.5, US 4, stepping a half size at a time.
Ring Sizes Around UK G US UK ISO / EU JP / KR Diameter (mm) Circumference (mm) 3 F 44 4 14.1 44.2 3.5 G 46 5 14.5 45.5 4 H 47 7 14.9 46.8 4.5 I 48 8 15.3 48 5 J 49 9 15.7 49.3
Frequently Asked Questions Does UK G round up or down in US? Round to the size that slides over the knuckle rather than the one that grips the base; a band that clears the joint but spins a little is safer than one that will not come off.
ℹ️
Note ISO 8653:2016 sets the size as inner circumference in mm; France and Germany label by the same number, so a ring bought anywhere in Continental Europe needs no conversion. Japan and Korea share one scale: 1 gou is a 13.0 mm bore and each step adds a third of a millimetre, so US 7 (17.3 mm) is 14 gou and 14 ho. Russia and the CIS size by inner diameter in mm to the nearest 0.5, so US 7 is a 17.5 there. A band wider than 6 mm is usually sized up about half a size, and a finger can swing close to a full size between a cold morning and a hot afternoon, so measure warm and late in the day. See a number that looks off? Report an error on this page.