How to Find Someone's Ring Size Secretly (5 Ways, Ranked)

You want the ring to fit, and you do not want to ask. Here are five ways, best first.

1. Borrow a ring for one minute

This is the only secret method that measures the real finger, so it is worth a little nerve.

Pick a ring they wear on the same finger you are buying for. A ring from the other hand is usually half a size out; a ring from a different finger is no use.
Open the ring sizer on your phone and calibrate it with a bank card. Do this beforehand — it is remembered.
Lay the ring on the circle and press + or − until the circle just fills the inside of the ring.
Screenshot the result, put the ring back.

You get the Indian, US, UK and EU size together, plus the inner diameter in millimetres — the number to give the jeweller.

2. Press it into soap

If you cannot sit with the ring and a phone, press it firmly into a bar of soap, or a piece of clay, and return it. The impression keeps the inner edge. Take the soap to a jeweller, or measure across the inner circle with a ruler: each 0.3 mm is one Indian size, so measure carefully and more than once.

3. Trace the inside

Put the ring on paper and trace inside it with a sharp pencil. Do it three times and measure the most consistent circle. A blunt pencil makes the circle a size too small, which is the wrong direction to be wrong in.

4. Slide it onto your own finger

Put their ring on one of your fingers and mark with a pen where it stops. A jeweller can size that spot on your finger. It is crude — good to a size or so — but it needs no tools and takes five seconds.

5. Ask someone who knows

A sister, a mother or a close friend may simply know, or can raise ring sizes in conversation without it meaning anything. It costs you the secret with one person. It is also the only method here that can ask about preferences as well as size.

What does not work

Guessing from height or build. People of the same height differ by four or five sizes.
Measuring while they sleep with string. String stretches, and a 1 mm error is a full Indian size. You will also probably wake them.
Using “the average size”. Shops stock Indian 10 to 14 for women and 16 to 22 for men because those are common — not because one of them is your partner’s.

If you are still unsure

Go slightly large, and choose a ring that can be resized. A plain band in gold or platinum can come down a size or two in a day. Eternity bands, tension settings, and tungsten or titanium cannot, so for those, methods 1 or 2 are the only safe ones.

Many jewellers will also propose with a placeholder: a simple band for the day, and the real ring sized together afterwards. No one has ever minded.

Questions people ask

What is the most accurate way to find a ring size secretly?

Borrow a ring they wear on the same finger and measure its inner diameter — on a calibrated on-screen sizer, or by taking it to a jeweller. A ring from the correct finger is the only secret method that measures the actual finger.

Does it matter which hand the ring comes from?

Yes. The dominant hand is usually about half a size larger. A ring from their right ring finger will be slightly big on the left if they are right-handed.

Should I size up or down if I am unsure?

Up, slightly. A ring that is a little loose still goes on when you propose, and most plain bands can be made smaller easily. One that stops at the knuckle cannot be worn at all.

Can every ring be resized?

No. Plain gold and platinum bands resize easily by a size or two. Eternity bands with stones all the way round, tension settings, and tungsten or titanium rings often cannot be resized at all, so accuracy matters more for those.

How to find someone's ring size secretly: five ways that work

The short answer