Ring Size Converter International Systems

Convert between international ring sizes with precision and confidence

Used by Jewellers and Clients Worldwide

Convert Ring Sizes Between Countries

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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.

AU / UK / Europe

US / Canada

Asia (HK / JP…)

Switzerland

Germany

France

Circumference (mm)

Select a size above to see all conversions

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).

Best time to measure: Measure at the end of the day when fingers are at their largest. Avoid cold weather or post-exercise. If between two sizes, always choose the larger.

Prepare your strip

Cut a thin strip of paper about 5 mm wide and 10 cm long, or use a piece of non-stretchy string.

Wrap your finger

Wrap the strip snugly around the base of the intended finger — not the knuckle. It should feel comfortable, not tight.

Mark the overlap

Use a pen to mark exactly where the strip meets itself, completing a full circle around your finger.

Measure in mm

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.

Look up your size

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.

Already own a ring?

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.

Typical women's sizes (AU)

KLMNOP

Inner circumference approx. 48–55 mm

Typical men's sizes (AU)

TUVWX

Inner circumference approx. 60–65 mm

Large knuckles? Take two measurements — one at the knuckle and one at the finger base — and choose the size in between.

Get Your Ring Size. Then Get the Right Ring.

Once you know your size, we help you choose the perfect emerald.