UK / AU
Ring sizes in Australia.
Australia and New Zealand use the British alphabetical scale, so a size N in Sydney is a size N in London. If you’re buying from an American retailer, you’ll need the numeric conversion below.
- The number means
- Wheatsheaf letters: size C = 40 mm circumference, 1.25 mm per letter
- Written as
- a letter — “N”
UK / AU sizes converted
Every row is calculated from the published standards, so the columns stay consistent with one another.
Scroll the table sideways to see every region
| UK / AU | Diameter | Circum. | US / CA | EU / ISO | France | DE / NL | Russia |
|---|---|---|---|---|---|---|---|
| H½ | 14.88 mm | 46.8 mm | 4 | 47 | 47 | 15 | 15 |
| I½ | 15.29 mm | 48.0 mm | 4½ | 48 | 48 | 15.5 | 15.5 |
| J½ | 15.69 mm | 49.3 mm | 5 | 49.5 | 49.5 | 15.5 | 15.5 |
| K½ | 16.10 mm | 50.6 mm | 5½ | 50.5 | 50.5 | 16 | 16 |
| L½ | 16.51 mm | 51.9 mm | 6 | 52 | 52 | 16.5 | 16.5 |
| M½ | 16.91 mm | 53.1 mm | 6½ | 53 | 53 | 17 | 17 |
| N½ | 17.32 mm | 54.4 mm | 7 | 54.5 | 54.5 | 17.5 | 17.5 |
| O½ | 17.73 mm | 55.7 mm | 7½ | 55.5 | 55.5 | 17.5 | 17.5 |
| P½ | 18.13 mm | 57.0 mm | 8 | 57 | 57 | 18 | 18 |
| Q½ | 18.54 mm | 58.2 mm | 8½ | 58 | 58 | 18.5 | 18.5 |
| R½ | 18.95 mm | 59.5 mm | 9 | 59.5 | 59.5 | 19 | 19 |
| S½ | 19.35 mm | 60.8 mm | 9½ | 61 | 61 | 19.5 | 19.5 |
| T½ | 19.76 mm | 62.1 mm | 10 | 62 | 62 | 20 | 20 |
| U½ | 20.16 mm | 63.3 mm | 10½ | 63.5 | 63.5 | 20 | 20 |
| V½ | 20.57 mm | 64.6 mm | 11 | 64.5 | 64.5 | 20.5 | 20.5 |
| W½ | 20.98 mm | 65.9 mm | 11½ | 66 | 66 | 21 | 21 |
| X½ | 21.38 mm | 67.2 mm | 12 | 67 | 67 | 21.5 | 21.5 |
| Z | 21.79 mm | 68.5 mm | 12½ | 68.5 | 68.5 | 22 | 22 |
| Z+1 | 22.20 mm | 69.7 mm | 13 | 69.5 | 69.5 | 22 | 22 |
Need a standard that isn’t shown? The full conversion chart lists all11 side by side.
Calibration
Calibrate with something in your pocket.
You don’t need a bank card. Our sizer knows the published diameter of coins from your currency, so you can calibrate with whatever is nearest.
A$1
25 mm across
Royal Australian Mint coin specifications
A$2
20.5 mm across
Royal Australian Mint coin specifications
€1
23.25 mm across
European Central Bank coin specifications
Buying from abroad
If you’re ordering from a retailer that uses a different scale, don’t translate the size yourself and hope. Send them the inside diameter in millimetres — every workshop in the world can work from that, and it removes the rounding step where errors creep in.
The reason is that the scales have different step sizes. A whole size in one system rarely lands exactly on a whole size elsewhere, so somebody has to round. Better that it’s the jeweller holding your measurement than a chart guessing at it.