Convert between international ring sizes with precision and confidence
Used by Jewellers and Clients Worldwide
Convert between AU/UK, US/Canada, Asia (HK/China/Taiwan/Japan/Singapore/Macau), Switzerland, Germany and France sizing systems.
Select your known size from any system — all equivalents update instantly below.
| Circ. (mm) |
Dia. (mm) |
US / Canada |
UK / Europe / Australia ★ |
Asia (HK, China, Taiwan, Japan, Singapore, Macau) |
Switzer- land |
Germany | France |
|---|
★ Australian sizes follow the UK alphabetical system — the primary standard used by Cullen Jewellery. | COMMON Most ordered sizes (women K–P, men T–W).
Cut a thin strip of paper about 5 mm wide and 10 cm long, or use a piece of non-stretchy string.
Wrap the strip snugly around the base of the intended finger — not the knuckle. It should feel comfortable, not tight.
Use a pen to mark exactly where the strip meets itself, completing a full circle around your finger.
Lay the strip flat against a ruler and measure the length in millimetres from the end to your pen mark. This is your inner circumference.
Match your circumference to the Full Size Chart tab, or enter it in the Size Converter above to find your AU and international sizes instantly.
Measure the inner diameter in mm with a ruler. Multiply by 3.1416 to get the circumference, then look up your size in the chart.
Inner circumference approx. 48–55 mm
Inner circumference approx. 60–65 mm
Once you know your size, we help you choose the perfect emerald.
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