How to Measure Your Ring Size at Home

Ring size is the inside size of a ring. In the US it’s given as a number (such as 7 or 7½); the UK uses letters, and Europe uses the inside circumference in millimeters. You can find yours at home in a few minutes.

Method 1: Measure a ring that already fits (most accurate)

1. Pick a ring that fits the same finger well.
2. Open our ring size finder and calibrate your screen with a card first.
3. Lay the ring on the circle and adjust until the circle’s edge lines up with the ring’s inside edge.
4. Read your size in US, UK, EU, Japan and India sizes.

No screen handy? Measure the ring’s inside diameter straight across with a millimeter ruler, then use the chart on the ring size finder page.

Method 2: Paper strip around your finger

1. Cut a thin strip of paper about 4 inches (10 cm) long.
2. Wrap it snugly around the base of your finger. It should slide over your knuckle with a little resistance.
3. Mark where the paper overlaps, then lay it flat and measure the length in millimeters.

That length is your finger’s circumference. The EU size is the same number rounded (54.4 mm → EU 54). To get a US size, type the length into the mm to ring size converter, or divide it by 3.1416 to get the diameter and use the formula below.

With a tape measure or string

A soft tape measure (the kind used for sewing) works like the paper strip: wrap it around the base of your finger, read where it overlaps, and enter the number in the mm to ring size converter. A rigid metal tape is too stiff to wrap snugly, so use it only to measure a piece of paper or string afterwards.

String works too, but it stretches and is easy to wrap loosely, which gives a size too big. Use thin, non-stretchy string or dental floss, keep it flat against the skin, and mark the overlap with a pen before you unwrap it. Measure two or three times.

Without measuring

No ruler, tape or ring to measure? You still have options:

• Use a ring you own on the on-screen ring sizer: no measuring, just match the circle.
• Print the free ring sizer: a paper sizing kit with a strip and circles.
• Compare with a coin. A US dime is 17.91 mm across, about the inside of a size 7¾ ring; a penny (19.05 mm) is about a 9; a nickel (21.21 mm) is about an 11¾. If a dime only just passes through a ring, the ring is about a size 7¾ to 8.
• Start from the averages. Most US women wear 5½ to 7½ and most men 8 to 12, but treat this as a last resort: sizes vary a lot.

Method 3: The math behind US ring sizes

US sizes grow by about 0.81 mm of inside diameter per whole size, starting from about 11.63 mm at size 0:

US size ≈ (inside diameter in mm − 11.63) ÷ 0.8128

Example: a 17.3 mm inside diameter gives (17.3 − 11.63) ÷ 0.8128 ≈ 7. Quarter and half sizes follow the same steps.

Tips for the right fit

• Measure at room temperature, later in the day. Cold fingers read small.
• Check the knuckle. If your knuckle is larger than the base of your finger, choose a size that passes over it.
• Wide bands fit tighter. For bands wider than about 6 mm, many jewelers suggest going up half a size.
• Measure three times and use the average, or the larger size if you’re between two.
• Buying a surprise gift? Borrow a ring the person wears on the same finger and measure it with Method 1.

For an expensive ring, confirm the size with a jeweler before ordering. Resizing isn’t possible for every design.