International conversion
Ring size chart
US sizes 3–13 in half-size steps, with inside circumference and diameter in millimetres.
EU/ISO sizes are shown as rounded inside circumference in millimetres. Regional conversions are nearest equivalents, not manufacturing tolerances.
| US / CA | UK / AU | EU / ISO | Japan | Circumference | Diameter |
|---|
How to measure ring size
Three practical methods
Measure the exact finger the ring will be worn on. Fit can vary by hand, temperature, knuckle size and band width.
Paper strip
Wrap a narrow, non-stretch strip around the base of the finger. Mark the overlap, lay it flat, and measure the length in millimetres. Repeat twice without pulling tight.
Existing ring
Choose a ring that fits the intended finger. Measure the inner diameter at its widest point. Do not include the metal edge in the measurement.
Printable sizer
Print at 100% or Actual Size—not Fit to Page. Check the 100 mm bar and card-size box before using the strip or ring circles.
Next step
Shop with a confirmed size
Use the converted size as a shortlist, then check the retailer’s own sizing notes before ordering.
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Ring sizing FAQ
Fit questions, answered
Small differences matter. A half size is only about 1.3 mm of circumference.
What if my measurement falls between two sizes?
Use the larger size as a starting point when the smaller option would be tight over your knuckle. Confirm with the seller’s chart, especially for wide or hard-to-resize bands.
Are men’s and women’s ring sizes the same system?
Yes. US ring sizes use the same scale regardless of gender. The typical ranges sold may differ, but a US size 7 means the same dimensions in any collection.
Do wide bands fit differently?
They often feel tighter because more metal contacts the finger. A slightly larger size may be more comfortable, but the exact adjustment depends on band width and construction.
When should I measure my finger?
Measure when your hands are at a comfortable room temperature. Finger size can change with heat, cold and activity, so repeat the measurement at different times before ordering.
Should I measure the diameter or circumference?
Use circumference when wrapping a strip around the finger. Use inner diameter when measuring a ring that already fits. Do not mix the two numbers in the converter.
Why does another chart show a slightly different conversion?
International systems do not always align perfectly, and manufacturers can use their own tolerances. This chart gives nearest equivalents; the retailer’s chart controls the final order.
How accurate is a printable ring sizer?
It can be useful only when printed at 100% or Actual Size. Verify both calibration references first. If they do not measure correctly, change the print settings and try again.
Can every ring be resized later?
No. Material, stones and construction can limit resizing. Eternity bands, tension settings, and some hard metals may be difficult or impossible to resize, so professional sizing matters before purchase.