UK Ring Size Guide
How to Measure

UK Ring Size Chart

The UK ring size system uses letters of the alphabet. Below is the full chart covering the most common women's sizes (H through T), with internal diameter in millimetres, circumference, and international equivalents.

Sizes L and M are highlighted as the most common UK women's ring sizes. Half sizes are available from most jewellers.

How to Measure Your Ring Size at Home

You don't need special tools. Here are three reliable methods:

Method 1: Existing Ring

Take a ring that fits the correct finger. Place it on a ruler and measure the internal diameter in millimetres. Match the measurement to the chart above. This is the most accurate home method.

Method 2: String or Paper Strip

Wrap a thin strip of paper or string around the base of the finger. Mark where it overlaps. Measure the length in millimetres — this is the circumference. Match it to the circumference column in our chart. Pull it snug but not tight — the ring needs to slide over the knuckle.

Method 3: Printable Ring Sizer

Many jewellers offer free printable ring sizers. Print at 100% scale (no “fit to page”), cut out, and place an existing ring over the circles. Double-check by measuring the printed test circle with a ruler to confirm the scale is accurate.

How to Measure Secretly (For Surprise Proposals)

This is the challenge every proposal planner faces. Here are tried-and-tested methods from people who've actually done it:

• Borrow a ring she already wears. Ideally one from her left ring finger. Take it to a jeweller or measure it yourself, then return it before she notices. Early morning while she's in the shower works well.
• Press a ring into soap or Blu Tack. Creates a clean impression you can measure later. Less risky than taking the ring out of the house.
• Trace the ring on paper. Place it flat on paper and draw around the inside edge with a pencil. Measure the circle's diameter.
• Ask her best friend or mum. The classic approach. Pick someone who can genuinely keep a secret. They may already know her size.
• Try on her rings yourself. See which of your fingers her ring fits on, then get THAT finger measured at a jeweller.
• Buy a ring sizer as a “gift for someone else.” Tell her you need her help sizing a ring for your mum or sister.

If all else fails: UK size L or M is the most common for women. Choose L if she has slimmer fingers, M if average. Most reputable jewellers offer one free resize within 30 days of purchase.

International Ring Size Conversion

If you're buying from an international jeweller or your partner knows their size in a different system, here's how the main systems compare:

• UK & Australia: Letter system (H, I, J, K, L, M...). The UK and Australia use the same system.
• US & Canada: Number system (4, 4.5, 5...). US 6 = UK L.
• Europe (EU): Based on internal circumference in millimetres. EU 51 = UK L.
• Japan: Own number system. Japan 11 = UK L.

The full conversion for each UK size is included in the chart above. When in doubt, provide the internal diameter in millimetres — it's universal and eliminates conversion errors.

Most Common UK Ring Size

According to UK jewellers, the most frequently sold women's engagement ring sizes are L and M, corresponding to an internal diameter of 16.1–16.5mm (US 6–6.5).

For men's rings, the most common sizes are R to T (US 9–10).

Ring size can vary between fingers by 1–2 letter sizes. The ring finger on the dominant hand is typically half a size larger than the same finger on the non-dominant hand. Make sure you're measuring the correct hand — engagement rings are traditionally worn on the left hand in the UK.

Tips for an Accurate Measurement

• Measure in the evening. Fingers swell throughout the day and are largest in the evening. A morning measurement may give you a size too small.
• Avoid extremes of temperature. Cold fingers are smaller; warm fingers are larger. Room temperature is ideal.
• Account for the knuckle. If knuckles are significantly wider than the base of the finger, go up half a size. The ring needs to slide over the knuckle but sit snugly at the base.
• Measure 2–3 times. Take multiple measurements on different days to get a consistent result.
• Consider the band width. Wider bands (over 4mm) fit tighter. If you're choosing a wide band, go up half a size.

Ring Resizing — What to Know

If you get the size wrong, don't panic. Most rings can be resized.

• Cost: £30–£80 at most jewellers. Many offer one free resize within 30 days.
• Range: Most rings can go up or down by 1–2 sizes comfortably.
• Time: Usually 3–7 working days. Some jewellers offer same-day service.
• Limitations: Eternity bands, tension-set rings, and tungsten or titanium bands generally cannot be resized. Check before purchase.

Read our metals guide for more on how different metals affect resizing options.

Frequently asked questions