Ring size FAQ
The questions we get asked most about ring sizing and conversion.
All questions
How do I convert a ring size between countries?
Use the converter on the home page: choose the system you know (US, UK, EU, Japan or mm), enter your size, and every other country appears at once. All conversions are based on the ring’s inner circumference, so they stay consistent both ways.
What is the average ring size?
For women, the most common sizes are US 6 to 6.5 (UK L to M, EU 52 to 53). For men, US 9 to 10.5 (UK R to U, EU 60 to 63) are typical. These are only averages, always measure for a real fit.
What is a US 7 in UK and EU sizes?
A US 7 is a UK N½ and an EU/ISO 54. Its inner circumference is about 54.4 mm and its inner diameter about 17.3 mm.
Are UK and Australian ring sizes the same?
Yes. The UK, Ireland, Australia and New Zealand all use the same A to Z letter system, so a UK N is an Australian N.
What does the EU / ISO number mean?
Under ISO 8653, the European size is the inner circumference of the ring in millimetres. An EU 54 ring is 54 mm around the inside.
How do Japanese ring sizes work?
Japan uses the JIS numeric system, based on inner diameter in roughly ⅓ mm steps. The numbers don’t match EU numbers: a US 7 is a Japan 14, not a Japan 54. China and South Korea commonly use the same scale.
What if I’m between two sizes?
Size up. A slightly loose ring is more comfortable and safer than one that won’t pass the knuckle, and jewellers can usually add sizing beads to snug it up later.
Does band width change the size I need?
Yes. Wide or comfort-fit bands (about 6 mm and up) sit tighter, so many people go up a quarter to a half size compared with a thin band.
What is the most accurate way to measure at home?
Measure the inner diameter of a ring that already fits, in millimetres, and convert it. If you have no ring, wrap string or paper around the finger for the circumference. The on-screen sizer combines both approaches.
When is the best time of day to measure?
The end of the day, when hands are warm and at their largest. Cold shrinks fingers by up to half a size; heat, salty food and exercise swell them.
Can a ring be resized later?
Most plain metal bands can be resized up or down by a size or two. Rings with stones all the way around (eternity bands), or made of tungsten or ceramic, usually cannot be resized, get those right the first time.
Why do online ring size charts disagree?
Charts get copied and occasionally a row slips, or diameter and circumference get mixed up. We generate every value from the ISO 8653 circumference formula and the JIS diameter standard and cross-check against known jeweller measurements, so the columns stay aligned.