Ring Size Calculator

How to measure your ring size at home

Method 1: measure a ring that fits

1. Choose a ring that fits the intended finger comfortably.
2. Measure the inside diameter – edge to edge across the widest point, not including the metal – with a ruler or calipers in millimetres.
3. Enter the diameter; the calculator converts it to sizes. A digital caliper gives the most accurate result.

Method 2: measure your finger

1. Wrap a thin strip of paper or non-stretch string around the base of your finger.
2. Mark where it overlaps, making sure it is snug but slides over the knuckle.
3. Lay it flat and measure the length in millimetres – that is your finger circumference.
4. Enter it in the calculator. Repeat two or three times at different times of day.

String and paper can stretch or be pulled too tight, so this method is less precise than measuring a ring. If you are between sizes, choose the larger one, or buy an inexpensive plastic ring sizer to confirm.

Ring size conversion chart

Half and quarter US sizes add about 0.4 mm and 0.2 mm to the diameter. Jewellers' charts differ slightly – especially for UK and Japanese sizes – so if a retailer publishes its own chart, use that.

Tips for an accurate fit

• Measure when your hands are warm and at a normal temperature – cold fingers shrink, while heat, exercise and salty food can make them swell.
• Measure the specific finger and hand: dominant-hand fingers are often slightly larger.
• If your knuckle is much wider than the base of your finger, measure both and choose a size between them so the ring slides over the knuckle but does not spin.
• Wide bands (about 6 mm or more) fit more snugly, so many people go up a quarter or half size.
• Comfort-fit bands, which are rounded inside, can feel looser than standard bands of the same size.

Sizing a ring as a surprise

Borrow a ring the person already wears on the same finger and measure its inside diameter, or press it into a bar of soap to make an impression you can measure later. Ask a close friend or family member, or compare against your own fingers. If in doubt, choose a slightly larger size: making a ring smaller is usually easier than making it larger, and many jewellers offer one free resize.

Can a ring be resized?

Most plain gold, silver and platinum bands can be resized by a jeweller, typically by up to two sizes. Rings set with stones all the way around (eternity bands), some patterned or engraved designs, and rings made of tungsten, titanium or ceramic are difficult or impossible to resize, so it is worth getting their size right first time.

Average ring sizes

Jewellers commonly report that many women's rings sell in US sizes around 6 to 7 and many men's rings around 9 to 10, but hands vary widely. Use a measurement rather than an average whenever you can.

Using a printable ring sizer

Printable sizers can work, but only if they print at exactly 100% scale. Check the printed ruler or reference line against a real ruler before you use it; even a small scaling change in the printer settings can make the result a size out. Cut carefully, wrap the strip snugly and read the number where the end meets the scale.

Engagement and wedding rings

Engagement and wedding rings are usually worn on the fourth finger of the left hand in many countries, and on the right hand in others, so measure the finger it will actually be worn on. If you plan to wear an engagement ring and a wedding band together, the combined width can feel tighter, so some people choose a quarter size larger for the band.

Thumb, index and stacking rings

Thumbs and index fingers are larger than ring fingers, so measure each finger separately. For stacking rings, measure with the stack in mind – several thin rings together behave like one wider band. Midi rings, worn above the knuckle, need a much smaller size and are best measured at that exact spot.

If a ring is slightly loose

A ring that is a little too big can be fitted with a sizing bead, a spring insert or a silicone ring guard instead of being resized. These are inexpensive and reversible, which suits rings that cannot be resized or fingers that change size with the seasons. A ring that is too tight should be resized rather than forced, because it can be difficult to remove if the finger swells.

Ring sizes for men and women

There is only one sizing scale – a US size 9 ring has the same inside diameter whether it is sold as a men's or women's ring. What differs is the typical width and style: men's rings are often wider, which can make them feel tighter at the same size. Use your measurement, then allow for band width as described above. Children's fingers are much smaller and change quickly, so size children's rings shortly before buying.