Ring Size Chart (US, UK, EU, mm and Circumference)
This chart lines up every common ring sizing system side by side. Find the size you already know in one column, then read across to the country or measurement you need.
Quick answer
Ring sizes are all based on the inside diameter of the band in millimetres. A US 7 is a UK N½, an EU 54 and measures 17.3 mm across the inside.
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Inside circumference, mm
Inside
Inside
Inside
Inside
Matched inside diameter 17.30 mm · circumference 54.35 mm
Full international chart
| US | UK | EU | FR | DE | CH | JP | BR | Ø mm | Ø in | Circ. mm |
|---|---|---|---|---|---|---|---|---|---|---|
| 3 | F | 44 | 44 | 14 | 4 | 4 | 7 | 14.00 | 0.551 | 43.98 |
| 3.5 | G | 45 | 45.5 | 14.5 | 5.75 | 5 | 8 | 14.40 | 0.567 | 45.24 |
| 4 | H | 47 | 46.75 | 14.75 | 7 | 7 | 9 | 14.80 | 0.583 | 46.50 |
| 4.5 | I | 48 | 48 | 15.25 | 8.25 | 8 | 10 | 15.20 | 0.598 | 47.75 |
| 5 | J½ | 49 | 49.25 | 15.75 | 9.5 | 9 | 11 | 15.60 | 0.614 | 49.01 |
| 5.5 | K½ | 50 | 50.5 | 16 | 10.75 | 10 | 12 | 16.00 | 0.630 | 50.27 |
| 6 | L½ | 52 | 51.75 | 16.5 | 12 | 12 | 13 | 16.45 | 0.648 | 51.68 |
| 6.5 | M½ | 53 | 53 | 17 | 13.25 | 13 | 14 | 16.90 | 0.665 | 53.09 |
| 7 | N½ | 54 | 54.25 | 17.25 | 14.5 | 14 | 15 | 17.30 | 0.681 | 54.35 |
| 7.5 | O½ | 56 | 55.5 | 17.75 | 15.75 | 15 | 16 | 17.70 | 0.697 | 55.61 |
| 8 | P½ | 57 | 56.75 | 18.25 | 17 | 16 | 17 | 18.10 | 0.713 | 56.86 |
| 8.5 | Q½ | 58 | 58 | 18.5 | 18.25 | 17 | 18 | 18.50 | 0.728 | 58.12 |
| 9 | R½ | 59 | 59 | 19 | 19.5 | 18 | 19 | 19.00 | 0.748 | 59.69 |
| 9.5 | S½ | 61 | 60.25 | 19.5 | 20.75 | 19 | 20 | 19.40 | 0.764 | 60.95 |
| 10 | T½ | 62 | 61.5 | 19.75 | 22 | 20 | 21 | 19.80 | 0.780 | 62.20 |
| 10.5 | U½ | 63 | 62.75 | 20.25 | 23.25 | 22 | 22 | 20.20 | 0.795 | 63.46 |
| 11 | V½ | 65 | 64 | 20.75 | 24.5 | 23 | 23 | 20.60 | 0.811 | 64.72 |
| 11.5 | W½ | 66 | 65.25 | 21 | 25.75 | 24 | 24 | 21.00 | 0.827 | 65.97 |
| 12 | X½ | 67 | 66.5 | 21.5 | 27 | 25 | 25 | 21.40 | 0.843 | 67.23 |
| 12.5 | Z | 68 | 67.75 | 22 | 28.25 | 26 | 26 | 21.80 | 0.858 | 68.49 |
| 13 | Z+1 | 70 | 69 | 22.25 | 29.5 | 27 | 27 | 22.20 | 0.874 | 69.74 |
How to read the chart
Every row in the table is one ring size. The last three columns show the physical measurement of the ring: inside diameter in millimetres, inside diameter in inches, and inside circumference in millimetres.
If you have measured your finger with string, you have the circumference. Find the closest circumference row and read across for your size in any country.
Which system does each country use?
- Letters (A–Z, often with ½ steps): United Kingdom, Ireland, Australia, New Zealand.
- Numbers (3–13 with ½ steps): United States, Canada, Mexico.
- Inside circumference in mm (44–70): most of Europe, following the ISO 8653 standard.
- Its own numeric scale: Japan (1–27), Switzerland, Brazil.
Common mistakes when using a chart
- Measuring the outside of a ring instead of the inside.
- Measuring a cold finger first thing in the morning, which reads a size small.
- Rounding a circumference down instead of up when you fall between rows.
- Using a size taken from a thin band to order a wide band.
Frequently asked questions
Is a UK ring size the same as a US ring size?
No. The UK uses letters and the US uses numbers. A UK N½ is a US 7, and each half-letter step in the UK is roughly a quarter of a US size.
What does the EU ring size number mean?
The European number is simply the inside circumference of the ring in millimetres, rounded to the nearest whole number. An EU 54 ring measures about 54 mm around the inside.
Keep reading
For an expensive ring, confirm the size with a jeweller before ordering — see the ring size FAQs for resizing advice.