Ring Size Calculator

Find your perfect ring size at home using string or paper. Converts between US, UK, and EU sizes instantly.

mm
US / Canada Size
8
UK / Australia
P 1/2
EU / Europe
57
Circumference
57.0 mm
Diameter
18.1 mm

How to Measure Your Ring Size at Home

You do not need to visit a jeweler to find your ring size. With a piece of string or a strip of paper, you can measure your finger at home in under a minute. Here are the two most reliable methods.

📏 String or Paper Method

Wrap a thin strip of paper or string snugly around the base of the finger you plan to wear the ring on. Mark the point where it overlaps. Lay the strip flat and measure the length in millimeters using a ruler. Enter that number above as your finger circumference.

💍 Existing Ring Method

Place a ring that fits well on a flat surface. Measure the inside diameter from edge to edge in millimeters. Select "Inner Ring Diameter" above and enter the measurement. This method tends to be the most accurate since you are measuring a rigid object.

Ring Size Conversion Chart

This table shows how US, UK, and EU ring sizes correspond to each other. The circumference column is the inner circumference of the ring in millimeters.

US SizeUK SizeEU SizeCircumference (mm)Diameter (mm)

Tips for Accurate Measurement

Measure at the right time. Fingers swell in hot weather and shrink in cold. For the best results, measure in the afternoon when your hands are warm and your body temperature is stable. Avoid measuring right after exercise, a shower, or first thing in the morning.

Measure several times. Take three readings on different occasions and use the average. If two measurements differ by more than a half size, measure again.

Account for knuckles. If your knuckle is significantly larger than the base of your finger, measure both the knuckle and the base, then pick a size somewhere between the two so the ring fits over the knuckle but does not spin freely.

Consider band width. Wide bands (6mm or more) fit tighter than thin bands. If you are buying a wide band, go up a half size from your measured size for a more comfortable fit.

Common Ring Sizes

The most popular ring sizes for women in the United States fall between sizes 5 and 7, with size 6 being the single most common. For men, sizes 8 through 11 are most typical, with size 10 being the most common. Engagement rings for women average between size 5.5 and 6.5. Ring sizes can also differ between your dominant and non-dominant hand, often by a quarter to half size.

International Sizing Systems Explained

The US and Canada share the same numerical sizing system, where sizes increase in half-size increments. The UK and Australia use an alphabetical system where each letter corresponds to roughly a half-size step. Europe uses a number that equals the inner circumference in millimeters, so an EU 56 ring has an inner circumference of 56mm. Japan uses its own numerical system that does not align directly with the US or EU. If you are shopping internationally, always convert using the circumference measurement for the most reliable comparison.

Ring Size FAQ

How do I measure my ring size at home?
Wrap a thin strip of paper or string snugly around the base of your finger. Mark where it overlaps, then measure the length in millimeters. Enter that circumference into the calculator above to find your ring size.
What is the most common ring size for women?
The most common ring size for women in the US is size 6 to 7, which corresponds to a finger circumference of about 51.5 to 54.4 mm. Engagement rings most commonly fall in the 5.5 to 6.5 range.
What is the most common ring size for men?
The most common ring size for men in the US is size 9 to 10, which corresponds to a finger circumference of about 59.5 to 62.1 mm.
Should I size up or down if I am between sizes?
If you are between two sizes, it is generally better to size up, especially for wider bands. A ring that is slightly loose is more comfortable than one that is too tight. You can always use a ring adjuster to snug up a slightly large ring.
Does temperature affect ring size?
Yes. Fingers swell in heat and humidity and shrink in cold weather. A ring that fits perfectly in summer may feel loose in winter. If you live in a place with big temperature swings, aim for a fit that works year-round by measuring at room temperature in the afternoon.
How do I convert between US and European ring sizes?
EU ring sizes equal the inner circumference of the ring in millimeters. A US size 7, for example, has a circumference of 54.4mm, so it is an EU 54. Use the conversion chart above or enter any measurement into this calculator for instant conversion.