Ring Size Converter
Convert ring sizes between US, UK, EU, and Indian systems
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Tip: measure the inner diameter of a well-fitting ring with a ruler or digital caliper. Accuracy to 0.1 mm matters — 0.4 mm difference equals one full ring size.
International Ring Size Chart
| Inner Diameter (mm) | US / Canada | UK / AU / SA | EU | India |
|---|---|---|---|---|
| 14.1 mm | 3 | F | 44 | 4 |
| 14.5 mm | 3.5 | G | 46 | 5 |
| 14.9 mm | 4 | H | 47 | 6 |
| 15.3 mm | 4.5 | I | 48 | 7 |
| 15.7 mm | 5 | J | 49 | 8 |
| 16.1 mm | 5.5 | K | 51 | 9 |
| 16.5 mm | 6 | L | 52 | 10 |
| 16.9 mm | 6.5 | M | 53 | 11 |
| 17.3 mm | 7 | N | 54 | 12 |
| 17.7 mm | 7.5 | O | 56 | 13 |
| 18.1 mm | 8 | P | 57 | 14 |
| 18.5 mm | 8.5 | Q | 58 | 15 |
| 18.9 mm | 9 | R | 59 | 16 |
| 19.4 mm | 9.5 | S | 61 | 17 |
| 19.8 mm | 10 | T | 62 | 18 |
| 20.2 mm | 10.5 | U | 63 | 19 |
| 20.6 mm | 11 | V | 65 | 20 |
| 21 mm | 11.5 | W | 66 | 21 |
| 21.4 mm | 12 | X | 67 | 22 |
Frequently Asked Questions
Wrap a narrow strip of paper or a piece of string around your finger. Mark where it meets and measure the length in millimeters — that is your inner circumference. Look up this value in the EU column of the chart above to find your European ring size. Alternatively, measure the inner diameter of a ring that fits well (across the inside) and enter it in the Diameter mm field.
Indian ring size 12 equals US 7, UK N, and EU 54 (54 mm inner circumference, 17.3 mm inner diameter). Indian jewellers such as Tanishq, Kalyan Jewellers, and Malabar Gold use a numeric system ranging from 1 to about 25. Look up your Indian size in the India column of the chart above to find the US, UK, and EU equivalents.
EU ring sizes are based on the inner circumference of the ring in millimeters, per ISO standard 8653. EU 54 = 54 mm inner circumference = 17.2 mm inner diameter. The EU standard is the most precise because it directly measures the actual ring dimension without conversion. Continental European jewellers in Germany, France, and the Netherlands all use this system.
US sizes use numbers (3–14, including half sizes like 7.5), while UK sizes use letters (A–Z). US 7 equals UK N, US 8 equals UK P, and US 9 equals UK R. UK sizing is also used in Australia, South Africa, and Ireland. To convert: a US size of 7 is approximately the 14th letter of the alphabet (N), giving you a rough guide of US size × 2 ≈ letter position.