SizeAtlas

Fit & Measurement

How to Measure Your Ring Size at Home

2 min read · Updated July 4, 2026

Ring sizing is unforgiving — a half size off and the ring either falls off or won't clear the knuckle. Skip the string trick; use one of these two methods instead.

Method 1: existing ring (most accurate)

  1. Take a ring that fits the intended finger.
  2. Measure the inner diameter in millimeters with a ruler or caliper.
  3. Match to the chart below.
Inner Ø (mm)USUKEU
15.75J½49½
16.56L½51¾
17.37N½54
18.18P½56¼
18.99R½59
19.810T½61¾

Method 2: paper strip circumference

  1. Cut a 6mm-wide strip of paper.
  2. Wrap around the finger snugly, past the knuckle.
  3. Mark where it overlaps, measure in mm.
  4. That's your circumference — divide by π (3.14) to get inner diameter.

When to measure

Fingers swell up to 5% during the day and shrink in cold weather. Measure late in the day, at room temperature, when your hands are relaxed.

Wide bands need up-sizing

A band wider than 6mm needs half a size up. A 10mm band at your normal size will feel tight — the additional surface area grips the finger differently.

Calculator

Ring size chart

Frequently asked questions

Can I size a surprise ring?
Borrow a ring they already wear on the intended finger and measure it. Don't guess from photos.
How do I resize a ring that's too small?
Most jewelers can resize up 2 sizes (silver, gold) or down 3 sizes. Eternity bands with stones all around cannot be resized.

Keep reading

Calculators

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Reviewed by the SizeAtlas editorial team · Last updated July 4, 2026