RING SIZE CHART: UK, US, & EUROPEAN GUIDE
- Leszek Drewniak
- May 5
- 2 min read
A beautiful ring loses its appeal if the fit is wrong. This international conversion guide helps you match measurements across the most common sizing systems—essential when buying antique and vintage rings globally.
Why Measurements Matter for Antique Rings
Antique rings are often unique, one-of-a-kind pieces. While many are listed in UK Letter Sizing, US or European clients need accurate conversions to buy with confidence.
Expert Tip: Letter and number sizes can vary slightly between jewelers, but Inside Diameter and Circumference (in mm) are fixed units. Always prioritize these measurements.
International Ring Size Conversion Table
UK (Letter) | US (Number) | Europe (ISO) | Inside Diameter | Circumference |
J | 5 | 49 | 15.7 mm | 49.3 mm |
K | 5.25 | 50 | 15.9 mm | 50.0 mm |
L | 5.75 | 51 | 16.3 mm | 51.2 mm |
M | 6.25 | 52 | 16.5 mm | 51.9 mm |
N | 6.75 | 54 | 17.1 mm | 53.8 mm |
O | 7.25 | 55 | 17.3 mm | 54.4 mm |
P | 7.75 | 56 | 17.7 mm | 55.7 mm |
Q | 8.25 | 57 | 18.1 mm | 57.0 mm |
R | 8.75 | 59 | 18.5 mm | 58.3 mm |
S | 9.25 | 60 | 19.0 mm | 59.5 mm |
How to Measure for the Best Fit
Measure an Existing Ring: Use a ruler to find the inside diameter straight across the center of a ring that fits you perfectly.
Measure Your Finger: Wrap a strip of paper around the base of your finger. Mark the overlap and measure the length in millimeters to find the circumference.
Antique-Specific Fitting Advice
Band Width: Wide bands feel tighter on the finger. If the antique ring has a substantial shank, consider going up half a size.
Top-Heavy Designs: Large Victorian or Art Deco settings may rotate if the fit is too loose. A snug fit is crucial for comfort.
A Note on Resizing Antique Jewelry
Not every period ring should be resized. Intricate engraved bands, delicate filigree, or original hallmarks can be compromised by significant adjustments.
At Old Cut Jewellery, we emphasize exact measurement before purchase to preserve the historical integrity of each piece. When in doubt, prioritize diameter and circumference—it is the safest route to a confident fit in the UK, US, and European markets.
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