Ring Size Converter

How to Measure Your Ring Size at Home (String, Paper, Printable Chart)

You do not need a jeweller to get a good ring size. A piece of string, a ruler and two minutes will get you within half a size, which is close enough for most rings.

Quick answer

Wrap string around the base of your finger, mark where it meets, measure the length in millimetres, then divide by 3.14 to get the inside diameter. Enter that number in the converter.

Instant Converter

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Inside circumference, mm

Inside

Inside

Inside

Inside

Matched inside diameter 17.30 mm · circumference 54.35 mm

Steps

  1. Step 1: Wrap

    Wrap a piece of string or a thin strip of paper snugly around the base of your finger.

  2. Step 2: Mark

    Mark the exact point where the two ends meet with a pen.

  3. Step 3: Measure

    Lay the string flat next to a ruler and read the length in millimetres. That is your finger circumference.

  4. Step 4: Divide

    Divide the circumference by 3.14 to get the inside diameter in millimetres.

  5. Step 5: Convert

    Enter the diameter or circumference into the ring size converter to get your US, UK, EU or Japanese size.

Method 2: measure a ring you already own

If you already have a ring that fits the right finger, place it on a ruler and measure straight across the inside, from one inner edge to the other. That number in millimetres is the inside diameter.

Measure the inside, never the outside. Including the metal on both sides can add a full size.

Method 3: use a printable chart

A printed chart lets you match an existing ring against a set of true-to-scale circles, or wrap a paper strip around your finger and read the size directly. Print it at 100% scale and check the calibration bar with a ruler before you use it.

Tips for an accurate reading

  • Measure in the late afternoon, when your fingers are at their normal size.
  • Measure at room temperature — cold fingers read small and hot fingers read large.
  • Take three readings and use the average.
  • The band has to pass your knuckle. If your knuckle is much wider than the base of your finger, measure both and choose something in between.
  • If you are between sizes, go up. Rings are easier to size down than up.

When to see a jeweller instead

For an engagement ring, an eternity ring or anything expensive, confirm the size with a jeweller using a proper steel sizer. Eternity rings and tension settings often cannot be resized later, so the first measurement has to be right.

Frequently asked questions

How accurate is the string method?

Within about half a size if you keep the string snug and measure carefully. It is accurate enough for fashion rings and for a first estimate on a proposal.

Should I measure the base of my finger or my knuckle?

Measure both. The ring needs to slide over the knuckle but sit snugly at the base, so choose a size between the two if they differ by more than half a size.

Keep reading

For an expensive ring, confirm the size with a jeweller before ordering — see the ring size FAQs for resizing advice.