How to Find Her Ring Size Without Her Knowing

Planning a surprise proposal? The ring has to fit, and asking outright gives the game away. These are the most reliable ways to find her ring size quietly, from the most accurate to the rough-and-ready.

1. Measure a ring she already wears

This is the most accurate method. Borrow a ring she wears on her ring finger (usually the fourth finger of the left hand) for a few minutes. Measure straight across the inside, edge to edge, in millimetres. That is the inside diameter; match it to the chart in our ring size guide.

No ruler to hand? Place the ring on a piece of paper and draw carefully around the inside with a sharp pencil, then measure the circle later.

Check which finger the ring is from. A ring worn on the right hand or on another finger may be a different size, and most people's dominant hand is slightly larger.

2. Press a ring into soap or clay

If you can only borrow a ring for a moment, press it halfway into a bar of soap or a piece of modelling clay to make an impression. Measure the inside of the impression later.

3. Ask someone she trusts

A close friend, sister or parent may already know her size, or can find out naturally, for example by trying on rings together while shopping. Make sure they can keep the secret.

4. Try her ring on your own finger

If all else fails, slide one of her rings onto your own finger and mark where it stops with a pen. A jeweller can then measure your finger at that point. It is rough, but better than a guess.

If you are between sizes

• Choose the larger size. A slightly loose ring is more comfortable than one that will not pass the knuckle.
• Wide bands, around 6 mm and up, fit more snugly, so many people go up half a size.
• Fingers are larger in warm weather and at the end of the day.

If it does not fit

Unworn pieces can be returned within 30 days of delivery; see our refund policy for the details. Tungsten rings cannot be resized, so check the size carefully for those.

Next step: choose the ring

Every ring page has a Find My Ring Size tool and a link to the full size chart. Not sure which style she would love? Take the 1-minute ring quiz on our Engagement Rings page, or read our guides to stone shapes and setting styles.