International Ring Size Conversion Chart: Australia, UK and US Ring Sizes
If you know your ring size in one sizing system but need to order in another, this chart will help. We take orders in both the Australian/UK alphabet system and the US numerical system.
You can also download and print the full chart as a PDF if you'd like to keep a copy.
If you don't yet know your ring size at all, our guide to finding your ring size covers every method from professional measuring to at-home techniques.
Australian/UK to US Ring Size Conversion Chart
| AU/UK Size | US Size | Internal Diameter (mm) | Internal Circumference (mm) |
|---|---|---|---|
| H | 4 | 14.88 | 46.8 |
| H½ | 4¼ | 15.09 | 47.4 |
| I | 4½ | 15.29 | 48.0 |
| J | 4¾ | 15.49 | 48.7 |
| J½ | 5 | 15.70 | 49.3 |
| K | 5¼ | 15.90 | 50.0 |
| K½ | 5½ | 16.10 | 50.6 |
| L | 5¾ | 16.31 | 51.2 |
| L½ | 6 | 16.51 | 51.9 |
| M | 6¼ | 16.71 | 52.5 |
| M½ | 6½ | 16.92 | 53.1 |
| N | 6¾ | 17.12 | 53.8 |
| N½ | 7 | 17.32 | 54.4 |
| O | 7¼ | 17.53 | 55.1 |
| O½ | 7½ | 17.73 | 55.7 |
| P | 7¾ | 17.93 | 56.3 |
| P½ | 8 | 18.14 | 57.0 |
| Q | 8¼ | 18.34 | 57.6 |
| Q½ | 8½ | 18.54 | 58.3 |
| R | 8¾ | 18.75 | 58.9 |
| R½ | 9 | 18.95 | 59.5 |
| S | 9¼ | 19.15 | 60.2 |
| S½ | 9½ | 19.35 | 60.8 |
| T | 9¾ | 19.56 | 61.4 |
| T½ | 10 | 19.76 | 62.1 |
| U | 10¼ | 19.96 | 62.7 |
| U½ | 10½ | 20.17 | 63.4 |
| V | 10¾ | 20.37 | 64.0 |
| V½ | 11 | 20.57 | 64.6 |
| W | 11¼ | 20.78 | 65.3 |
| W½ | 11½ | 20.98 | 65.9 |
| X | 11¾ | 21.18 | 66.6 |
| X½ | 12 | 21.39 | 67.2 |
| Y | 12¼ | 21.59 | 67.8 |
| Z | 12½ | 21.79 | 68.5 |
| Z½ | 12¾ | 22.00 | 69.1 |
| - | 13 | 22.20 | 69.7 |
| Z1 | 13¼ | 22.40 | 70.4 |
| - | 13½ | 22.61 | 71.0 |
| Z2 | 13¾ | 22.81 | 71.7 |
| Z3 | 14 | 23.01 | 72.3 |
| - | 14¼ | 23.22 | 72.9 |
| Z4 | 14½ | 23.42 | 73.6 |
| - | 14¾ | 23.62 | 74.2 |
| Z5 | 15 | 23.83 | 74.8 |
| - | 15¼ | 24.03 | 75.5 |
| Z6 | 15½ | 24.23 | 76.1 |
| - | 15¾ | 24.43 | 76.8 |
| - | 16 | 24.64 | 77.4 |
Our rings are available in Australian/UK sizes H to Z+6. US sizes are welcome - select "Other - will advise" from the size dropdown menu and leave a note with your US size during checkout.
Which Ring Sizing System Does Australia Use?
Australia uses the same alphabet-based system as the UK, Ireland, New Zealand and South Africa. Sizes run from A (very small) upward, with half sizes available for many letters. Most adult ring sizes fall between H and Z.
The United States and Canada use a numerical system starting from size 1. US sizes and Australian/UK sizes don't follow a simple formula - the conversion varies slightly across the range, which is why a chart is more reliable than trying to calculate it.
Wide Band Ring Sizing
If you're ordering a wide band ring - such as one of our fidget rings and spinner rings or our men's sterling silver signet ring - the standard conversion chart still applies, but you will likely need to order a larger size than you would for a narrow band.
Wide band rings sit higher on the finger and compress more surface area, which makes them feel tighter than a standard band in the same size. Most people need to go half a size to a full size larger for wide band rings. If you are unsure, your local jeweller can measure your wide band size free of charge.
Buying a Ring as a Gift
If you're buying a ring as a gift for someone who wears rings in the US system and you need to convert their size to Australian/UK, use the table above to find the equivalent. If you're unsure of their size at all, our guide to finding your ring size includes practical advice for measuring someone else's finger or using an existing ring as a reference.
Browse Our Handmade Silver Rings
All of our rings are made to order in your chosen size. We make sterling silver stacking rings, fidget rings and anxiety rings, wedding rings, a men's signet ring and a range of gemstone rings. All our rings are handmade in Adelaide, South Australia by Rebecca Cordingley.
If you have any questions about sizing before placing your order, contact us and we'll help you find the right size.