QuickCheckToolsRing size chart
Convert ring sizes between US, UK and European systems, or find your size from a measurement in millimetres.
Ring size conversion chart
| US / Canada | UK / Australia | Europe | Diameter | Circumference |
|---|---|---|---|---|
| 3 | F | 44 | 14.1 mm | 44.2 mm |
| 3½ | G | 45 | 14.5 mm | 45.5 mm |
| 4 | H½ | 47 | 14.9 mm | 46.8 mm |
| 4½ | I½ | 48 | 15.3 mm | 48.0 mm |
| 5 | J½ | 49 | 15.7 mm | 49.3 mm |
| 5½ | K½ | 51 | 16.1 mm | 50.6 mm |
| 6 | L½ | 52 | 16.5 mm | 51.9 mm |
| 6½ | M½ | 53 | 16.9 mm | 53.1 mm |
| 7 | N½ | 54 | 17.3 mm | 54.4 mm |
| 7½ | O½ | 56 | 17.7 mm | 55.7 mm |
| 8 | P½ | 57 | 18.1 mm | 57.0 mm |
| 8½ | Q½ | 58 | 18.5 mm | 58.2 mm |
| 9 | R½ | 60 | 18.9 mm | 59.5 mm |
| 9½ | S½ | 61 | 19.4 mm | 60.8 mm |
| 10 | U | 62 | 19.8 mm | 62.1 mm |
| 10½ | V | 63 | 20.2 mm | 63.3 mm |
| 11 | W | 65 | 20.6 mm | 64.6 mm |
| 11½ | X | 66 | 21.0 mm | 65.9 mm |
| 12 | Y | 67 | 21.4 mm | 67.2 mm |
| 12½ | Z | 68 | 21.8 mm | 68.5 mm |
| 13 | 70 | 22.2 mm | 69.7 mm |
How to measure your ring size
Cut a thin strip of paper, wrap it around the base of your finger, and mark where the end overlaps. Lay it flat and measure to the mark in millimetres: that's your finger's circumference. If you already have a ring that fits, measure straight across the inside edge instead for its diameter. Measure at the end of the day, when fingers are slightly larger.
Questions
How do I measure my ring size at home?
Wrap a strip of paper or string around the base of your finger, mark where it overlaps, and measure the length in millimetres. That is your circumference: enter it above. Or measure straight across the inside of a ring that fits to get its diameter.
What is a size 7 ring in mm?
A US size 7 has an inside diameter of 17.3 mm and an inside circumference of 54.4 mm. That is a UK N½ and about a European 54.
How do UK and US ring sizes compare?
UK sizes use letters and US sizes use numbers. Roughly, one UK letter is half a US size: UK N½ is US 7, P½ is about US 8 and L½ is about US 6.
What is the European ring size?
In Europe (ISO 8653), the ring size is the inside circumference in millimetres. A size 54 ring measures 54 mm around the inside.
What if I'm between sizes?
Go up to the larger size, especially for wide bands, which fit tighter. Fingers are also slightly bigger in warm weather and at the end of the day.
Why do charts disagree slightly?
Different countries use different standards, and converting between them rarely lands exactly on a size, so jewellers round differently. Charts can differ by up to half a size, so the millimetre measurement is the most reliable thing to give a jeweller.
US sizes follow the standard 0.032 inch per size scale; European sizes follow ISO 8653; UK sizes follow BS 6820. Charts can differ by up to half a size between jewellers.