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Free International Size Converter

Ring Size Converter

Convert ring sizes between US, Canada, UK, Australia, Europe and Japan. Instantly check equivalent sizes, inner diameter and circumference in millimeters.

Convert Your Ring Size

Choose your current sizing system and ring size.

Equivalent Ring Sizes

US / Canada 7
UK / Australia N 1/2
Europe 54
Japan 14
Inner Diameter 17.35 mm
Circumference 54.51 mm
Ring sizing may vary slightly between jewelry brands and manufacturers. Use the result as a practical sizing reference.

Find Ring Size From Measurement

Enter diameter or circumference in millimeters.

Simple Process

How the Ring Size Converter Works

Convert your ring size between international standards in three simple steps.

01

Choose Your Size System

Select the sizing system you currently know, including US, UK, European or Japanese sizing.

02

Select Your Ring Size

Choose your current ring size from the list. The tool automatically matches it with the appropriate conversion data.

03

View Your Conversion

See equivalent US, UK, EU and Japanese sizes together with diameter and circumference.

What Is a Ring Size Converter?

A Ring Size Converter helps you translate one ring sizing standard into another. This is especially useful when buying jewelry from another country or shopping from an international online store.

Ring sizing systems are not identical around the world. US and Canadian sizes normally use numbers, while UK and Australian sizes commonly use letters. European sizing usually uses larger numerical values.

Why Ring Sizes Differ by Country

Different regions developed their own jewelry sizing standards. Because of this, a US size 7 does not have the same size label in the UK, Europe or Japan even though the physical ring can be approximately the same size.

Diameter and Circumference

Ring diameter measures straight across the inside of the ring. Circumference measures the entire distance around the inside edge. These measurements provide a useful way to compare ring sizes even when regional sizing labels are different.

Size Reference

International Ring Size Chart

Compare common US, UK, European and Japanese ring sizes with approximate millimeter measurements.

US / Canada UK / Australia Europe Japan Diameter (mm) Circumference (mm)
3 F 44 4 14.05 44.14
3.5 G 1/2 45 5 14.45 45.40
4 H 1/2 46 7 14.86 46.68
4.5 I 1/2 48 8 15.27 47.97
5 J 1/2 49 9 15.70 49.32
5.5 K 1/2 50 10 16.10 50.58
6 L 1/2 52 12 16.51 51.87
6.5 M 1/2 53 13 16.92 53.16
7 N 1/2 54 14 17.35 54.51
7.5 O 1/2 56 15 17.75 55.76
8 P 1/2 57 16 18.19 57.15
8.5 Q 1/2 58 17 18.59 58.40
9 R 1/2 59 18 18.89 59.34
9.5 S 1/2 61 20 19.41 60.98
10 T 1/2 62 21 19.84 62.33
10.5 U 1/2 63 22 20.20 63.46
11 V 1/2 65 23 20.68 64.97
11.5 W 1/2 66 24 21.08 66.22
12 X 1/2 68 25 21.49 67.51
12.5 Y 1/2 69 26 21.89 68.77
13 Z 1/2 70 27 22.33 70.15

Important: International ring size conversions are approximate. Jewelry manufacturers can use slightly different tolerances. For expensive, custom or permanent jewelry, professional sizing is recommended.

Common Questions

Ring Size Converter FAQs

Answers to common questions about ring size conversions and measurements.

Choose US / Canada from the sizing system and select your current US ring size. The tool will instantly display the corresponding UK size.

US and Canadian jewelers generally use the same numerical sizing system, including common half sizes.

Measure straight across the inside of a ring that already fits. Enter that measurement in millimeters into the measurement finder above to find the nearest standard ring size.

Diameter is the straight distance across the inside of a ring. Circumference is the complete distance around the inside edge.

The converter uses commonly referenced international size equivalents. However, manufacturers and jewelry brands can vary slightly, so the result should be treated as a practical reference.

Wider bands can feel tighter than narrow bands, so some people prefer a slightly larger size. The ideal adjustment depends on the ring design and personal comfort.