International Ring Size Conversion: Complete Guide

Ring sizing systems vary significantly around the world. If you're shopping from an international retailer or buying a ring abroad, knowing how to convert between systems is essential. This guide covers every major sizing standard.

The Major Ring Sizing Systems

There are five primary ring sizing systems used globally:

US/Canada: Numerical (3–13+)
UK/Ireland/Australia: Alphabetical (A–Z+)
Europe (ISO): Circumference in mm (41–76)
Japan/Asia: Numerical (1–27)
Switzerland: Numerical (1–27, different scale)

Complete International Conversion Chart

US	UK	EU	Japan	Diameter (mm)
4	H	47	7	14.9
4.5	I	48	8	15.3
5	J½	49	9	15.7
5.5	K½	51	11	16.1
6	L½	52	12	16.5
6.5	M½	53	13	16.9
7	N½	54	14	17.3
7.5	O	56	16	17.7
8	P½	57	17	18.2
8.5	Q	58	18	18.6
9	R½	60	20	19.0
9.5	S½	61	21	19.4
10	T½	62	22	19.8
11	V	64	24	20.6
12	X	67	27	21.4

Quick Conversion Formulas

US to EU: (US size × 2.55) + 40 = EU size EU to US: (EU size − 40) ÷ 2.55 = US size UK to EU: UK letter position × 1.25 + 36.5 (approximate)

For precise conversions, always use the chart above rather than formulas, as the formulas are approximations.

Shopping on International Platforms

Etsy

Etsy sellers are based worldwide. Always check the seller's location and which sizing system they use. Most US-based sellers use US sizes; UK sellers use UK sizes.

AliExpress and Asian Retailers

Chinese and Korean jewelry retailers typically use Asian (Japanese) sizing. A size 10 in Asian sizing is roughly a US size 5 — very different from a US size 10.

Always check: When buying from Asian retailers, look for the diameter in millimeters rather than relying on the size number alone.

European Luxury Brands

Brands like Cartier, Bulgari, and Pandora use European (ISO) sizing. Pandora, for example, lists sizes as 48, 50, 52, 54, 56, 58, and 60.

How to Avoid Sizing Mistakes

Always ask for the diameter in mm — this is universal and unambiguous
Confirm the sizing system before ordering
Check the return/resize policy before purchasing internationally
Use our conversion chart rather than trusting the seller's conversion

When Rings Arrive in the Wrong Size

International returns can be complicated. Before buying from overseas:

Check if the seller offers resizing
Understand the return shipping cost
Consider whether a local jeweler can resize the ring if needed

Most simple bands can be resized by any jeweler. Rings with stones around the entire band (eternity rings) or very intricate settings may be difficult or impossible to resize.

Keep this guide handy for your next international ring purchase — it could save you a costly mistake.