Ring Size Chart: Complete Guide to US, UK & EU Sizes

Ring size charts can seem complicated when you're shopping across different countries. A US size 7 is a UK size N, and a EU size 54 — and that's just the beginning. This guide breaks down every major ring sizing system so you can shop confidently anywhere in the world.

US Ring Size Chart

The United States uses a numerical scale that typically runs from size 3 to size 13, with half-size increments available. Each full size represents an increase of approximately 0.4mm in diameter.

US Size	Diameter (mm)	Circumference (mm)
4	14.9	46.8
5	15.7	49.3
6	16.5	51.9
7	17.3	54.4
8	18.2	57.0
9	19.0	59.5
10	19.8	62.1

UK and Ireland Ring Sizes

The UK system uses letters, starting at A and going through Z and beyond. Most women fall between sizes J and O, while men typically range from P to V.

UK Size	US Size	Circumference (mm)
J	4.75	47.7
L	5.75	51.2
N	7.0	54.4
P	8.0	57.8
R	9.0	61.0

European (ISO) Ring Sizes

European sizes correspond directly to the inner circumference of the ring in millimeters. This makes them the most precise system — a EU size 54 means the inner circumference is exactly 54mm.

EU Size	US Size	UK Size
47	4	H
49	5	J½
52	6	L½
54	7	N
57	8	P½
60	9½	S

Japanese and Asian Ring Sizes

Japan uses a numerical system similar to the US but with different values. Asian sizes (used in China, Japan, South Korea) typically run from 1 to 27.

A Japanese size 10 is roughly equivalent to a US size 5, and the sizes increase by approximately the same increments.

How to Use This Chart

1. Measure your finger using our online ring sizer or the string method
2. Find your measurement in the circumference column (mm)
3. Read across the row to find your size in any system
4. When between sizes, always round up for comfort

Tips for International Shopping

Check the listing's size system: Always confirm which sizing standard the seller is using. Many online marketplaces serve multiple countries simultaneously.

Consider ring width: Wider rings (above 6mm) sit higher on the finger and can feel tighter. You may need to go up half a size for wide bands.

Account for seasonal changes: Your fingers can be up to a full size larger in summer heat than winter cold. Measure at a neutral temperature.

When in doubt, size up: It's easier and cheaper to resize a ring down than to size it up.

Quick Conversion Tips

• US to EU: Multiply US size by 2.55, then add 40
• EU to US: Subtract 40, then divide by 2.55
• UK letter J = US size 5 (easy reference point)

Keep this guide bookmarked for your next international ring purchase!