Find your perfect ring size with multiple measurement methods and accurate conversions across US, UK, European, and Asian sizing systems.
Choose your preferred measurement method below:
Measure the inner diameter of a ring that fits well on the intended finger.
Actual size preview
Print these tools at 100% scale (no scaling) for accurate measurements.
Complete conversion table for all major sizing systems. Click column headers to sort.
| US Size ↕ | UK Size ↕ | EU Size ↕ | Inner Diameter (mm) ↕ | Circumference (mm) ↕ |
|---|
US Size 6-7 (16.5-17.3mm diameter)
US Size 9-10 (19.0-19.8mm diameter)
Numbered system (3-15)
Uses numerical sizing with half sizes. Most common system in North America.
Letter system (A-Z)
Uses alphabetical sizing starting from A. Adult sizes typically range F-Z.
Circumference (44-70)
Based on inner circumference in millimeters. Most precise system.
Numbered (1-30)
Uses numerical system with different scaling than US sizes.
Wrap a string around your finger where the ring will sit. Mark where it overlaps, then measure the marked length. This gives you the circumference. Works best with non-stretchy string or dental floss.
Cut a thin strip of paper (about 1cm wide). Wrap it around your finger, mark the overlap, and measure. Paper is stiffer than string and may give a more accurate measurement for some people.
Use a ring that already fits well. Measure the inner diameter with a ruler or calipers. This is the most accurate method if you have a well-fitting ring for the same finger.
Professional jewelers use ring mandrels and sizers for the most accurate measurements. Many jewelers offer free sizing services, especially if you're considering a purchase.
Wider rings feel tighter and may require a larger size:
Thin bands (2-4mm): Use your measured size
Medium bands (4-6mm): Consider 0.25 size larger
Wide bands (6mm+): Usually need 0.5-1 size larger
Flat interior surface. True to size measurements.
Rounded, domed interior. Usually requires 0.5 size smaller than standard fit.
The most common women's ring size is US size 6-7, which corresponds to an inner diameter of 16.5-17.3mm. However, sizes can vary significantly based on height, weight, and genetics.
The most accurate home method is measuring an existing ring's inner diameter. If you don't have one, use the string method: wrap string around your finger, mark the overlap, and measure the length. Measure in the evening when hands are warm.
European ring sizes correspond to the inner circumference in millimeters. For example, US size 6 = EU size 51.9, and US size 7 = EU size 54.4. Use our conversion chart above for exact measurements.
Size up for wide bands. Bands wider than 6mm typically require 0.5-1 size larger than your measured size because they cover more surface area and feel tighter on your finger.
Yes, ring size can change due to weight fluctuations, temperature, time of day, pregnancy, aging, and medical conditions. It's normal for size to vary by 0.25-0.5 sizes throughout the day.
If you're between sizes, consider the ring width and your lifestyle. For thin bands or active lifestyles, choose the smaller size. For wide bands or if you have large knuckles, choose the larger size.