Ring Size Converter – US, UK, EU, JP & CN
Converted Sizes
Full Ring Size Chart
| US | UK | EU | JP | CN | Dia (mm) | Circ (mm) |
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How Ring Sizes Are Measured
Ring sizes are based on the inner circumference or diameter of the ring band. Different countries use different numbering systems, but they all correspond to the same physical measurements. The US system uses a numerical scale where each full size represents approximately 0.8mm in diameter.
To measure your ring size at home, wrap a string snugly around your finger, mark the overlap point, and measure the length in millimeters. This gives you the circumference. For the most accurate results, measure at the end of the day when fingers are slightly larger, and ensure the ring will fit over your knuckle.
Japanese ring sizes use a numbered system starting from 1, with each size being 1mm apart in circumference. Chinese sizes follow a similar pattern. When ordering rings internationally, always verify the sizing system used by the retailer. For engagement and wedding rings, professional sizing at a jeweler is recommended.
Frequently Asked Questions
How do I measure my ring size at home?
Wrap a thin strip of paper or string around your finger, mark where it overlaps, then measure the length in millimeters. This gives you the circumference. Divide by 3.14159 (pi) to get the inner diameter. Use the conversion table to find your size.
What is the most common ring size?
For women in the US, size 6-7 (16.5-17.3mm diameter). For men, US size 9-10 (19.0-19.8mm diameter). However, ring sizes vary widely.
Do ring sizes differ between countries?
Yes, ring sizing systems vary significantly. The US uses a numerical scale (1-16), the UK uses letters (A-Z), Europe uses circumference in millimeters, and Japan uses a numbered system starting from 1.
Should I size up or down if between sizes?
If between sizes, size up for comfort. Fingers swell in hot weather or after exercise. For wide-band rings, go up an additional half size as they fit more snugly.