How to Measure Women's Ring Size UK

Cut a strip of paper 1 cm wide and 10 cm long — any standard paper works

Wrap snugly around the base of your ring finger (left hand, third finger for UK engagement rings)

The strip must slide over your knuckle — if it can't, size up

Mark the exact overlap point with a pen — do not guess

Remove and lay flat. Measure from the start to the mark in millimetres

Repeat 3 times on different days, average the three mm readings, then use the calculator below

Cut a piece of non-stretchy string, thread, or dental floss — approximately 15 cm long

Wrap once around the base of the finger you wish to size

Using a pen, mark the string where it completes the full loop

Lay the string against a mm ruler. Measure from the start of the string to the pen mark in mm

⚠️ Do not use elastic or stretchy thread — it will give a reading smaller than your actual size

Enter the mm reading into the calculator below — this is your finger circumference

Choose a ring that fits comfortably on the exact finger you want to size — not from a different finger

Place the ring on a flat surface. Using a mm ruler or digital calipers, measure the inner diameter across the widest point

This gives you the diameter in mm — enter it into the calculator and select "Diameter (mm)"

⚠️ If the ring is not a perfect circle (oval, square), use the average of the widest and narrowest inner measurements

💡 Digital calipers (available from £8 online) give ±0.01 mm accuracy — the most precise at-home method available

Print the ruler below at exactly 100% scale — never select "fit to page" or "scale to fit"

Verify before cutting — place a real ruler against the printed 50 mm mark to confirm it is exactly 50 mm

Cut a 1 cm wide strip along the ruler. Wrap around your finger at the base

Mark the overlap point, then read the mm value directly off the printed ruler

⚠️ Printer calibration varies — even a 2–3% scaling error equals one full UK ring size difference

Use digital calipers (available from £8–£15 on Amazon UK). Open the inner jaws wide enough to fit inside a ring

Place caliper inner jaws inside the ring and open until both jaws touch the interior edges

Read the diameter in mm from the digital display — this is your ring's inner diameter

Enter into the calculator below using "Diameter (mm)" option for your UK size

💡 Also useful for measuring your finger directly — gently close outer jaws around the finger to get diameter directly

Visit any UK jeweller — Goldsmiths, H.Samuel, Ernest Jones, Beaverbrooks, or Hatton Garden — and ask for a ring sizing. It is always free

The jeweller will use a ring mandrel and sizing set — a graduated set of metal rings in every UK half-size — to find your exact size

Ask to be sized in the afternoon or evening when your fingers are at their natural largest

Request your size in UK letter format — some stores default to EU or US sizes

💡 Best option for expensive engagement rings, wide wedding bands, or if you are regularly between sizes