International Ring Size Chart

Comprehensive ring size conversion table covering US, UK, European, Japanese, and other international sizing systems. Includes inside diameter and circumference measurements in millimeters.

Ring Size Conversion Chart

US/Canada	UK/Australia	European	Japan	Diameter (mm)	Circumference (mm)
3	F	44	4	14.1	44.2
3.5	G	45	5	14.5	45.5
4	H	46.5	7	14.9	46.8
4.5	I	48	8	15.3	48.0
5	J	49	9	15.7	49.3
5.5	K	50	10	16.1	50.6
6	L	51.5	12	16.5	51.9
6.5	M	53	13	16.9	53.1
7	N	54	14	17.3	54.4
7.5	O	55.5	15	17.7	55.7
8	P	57	16	18.1	57.0
8.5	Q	58	17	18.5	58.3
9	R	59	18	18.9	59.5
9.5	S	60.5	19	19.4	60.8
10	T	62	20	19.8	62.1
10.5	U	63	22	20.2	63.4
11	V	64	23	20.6	64.6
11.5	W	65.5	24	21.0	65.9
12	X	67	25	21.4	67.2
12.5	Y	68	26	21.8	68.5
13	Z	69	27	22.2	69.7
13.5	Z+1	70.5	28	22.6	71.0
14	Z+2	72	29	23.0	72.3
15	Z+4	74	30	23.8	74.8
16	Z+6	76	32	24.6	77.4

US & Canada

• Uses numerical sizes from 1 to 16+
• Half sizes are common (6.5, 7.5, etc.)
• Quarter sizes available from some jewelers
• Most common women's size: 6-7
• Most common men's size: 9-10

UK, Ireland & Australia

• Uses alphabetical sizes from A to Z
• Sizes continue as Z+1, Z+2, etc.
• Half sizes exist (H½, etc.)
• Most common women's size: L-N
• Most common men's size: R-T

European (France, Germany, Scandinavia)

• Based on inner circumference in mm
• Sizes typically range from 44 to 76
• Some countries use diameter instead
• Most common women's size: 50-54
• Most common men's size: 58-64

Japan, China & Korea

• Japan uses numerical system (1-30)
• China often uses diameter in mm
• Korea uses similar system to Japan
• Vintage Japanese jewelry may use old system
• Hong Kong uses a unique system

How to Measure Ring Size at Home

Method 1: Use an Existing Ring

Find a ring that fits the intended finger well
Measure the inside diameter with a ruler (in mm)
Match to the chart above
If between sizes, round up for wider bands

Method 2: String/Paper Strip

Cut a thin strip of paper or use string
Wrap snugly around the finger base
Mark where it overlaps
Measure the length in mm (circumference)
Match to the chart above

Pro Tips

• Measure at the end of the day when fingers are largest
• Avoid measuring when cold (fingers shrink)
• Wide bands (6mm+) need a half-size larger
• Knuckles larger than finger base? Size for the knuckle
• When in doubt, visit a jeweler for professional sizing

Band Width and Ring Size

Here's something most size charts don't tell you: band width affects how a ring fits. A 2mm band in size 7 will feel very different from an 8mm band in the same size.

The General Rule

For bands wider than 6mm, go up a half size. For very wide bands (10mm+), consider going up a full size. The wider the band, the more it grips the finger.

Comfort Fit vs. Standard Fit

"Comfort fit" bands have a domed interior that makes them easier to slide on and off. They typically run about a quarter size larger than standard flat-interior bands. If you're between sizes, comfort fit bands give you more flexibility.

Vintage Ring Sizing

Many vintage rings use older sizing standards or have been resized over the decades. The shank may be slightly out of round or have solder marks from previous sizings. When buying vintage, always verify the size with actual measurements rather than relying solely on what the seller states.

A Note on Resizing

Not all rings can be resized. Eternity bands, tension settings, and some vintage pieces may be difficult or impossible to resize without damage. Full bands with stones all around can only be sized by adding/removing stones—a major undertaking.

Before purchasing a ring that doesn't fit perfectly, ask about resizing limitations. Some designs simply need to fit from the start.

Related Guides & Resources

Metals Converter →Carat Calculator →How to Authenticate →Jewelry Glossary →All Tools →

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