How to get ring size right, especially as a surprise

Most sizing problems are not measurement errors. They are timing errors.

Fingers change size during the day

A finger is smallest first thing in the morning and in cold weather. By the end of a warm day it can be half a size larger.

Measure in the evening, at room temperature. A ring sized at 8am in January will feel tight in June, and the wearer will assume you got it wrong.

Three things that shift the answer

Band width. Anything over about 6mm sits across more of the finger and feels tighter at the same measurement. Go up a quarter to a half size.

The knuckle. The ring has to pass the knuckle but sit at the base. If there is a big difference between the two, size for the knuckle — a small internal bead stops it spinning afterwards.

Which hand. The dominant hand is typically a quarter to half a size larger. Measure the finger the ring is actually for.

If it is a surprise

In rough order of reliability:

1. Borrow a ring she already wears on that finger, and trace the inside diameter. Not a ring from a different finger — they differ more than people expect.
2. Ask someone with the same hand size. A sister or close friend can often try one on.
3. Size up, not down. A ring slightly too large can be worn on a different finger until it is resized. Too small cannot be worn at all, and the moment is spoiled.

If you are choosing between two sizes for a proposal, take the larger one and tell us. We would rather resize afterwards than have it not go on.

What can and cannot be resized

Most plain bands resize up to two sizes, free within 90 days of purchase.

Eternity bands, pavé-set designs and bangles cannot be resized — the stones run the whole way round, so there is nowhere to cut. On those, get the size right first, and ask us if there is any doubt.

When in doubt, ask

Tell us the piece and what you know, and we will tell you what is safe. Guessing costs you a return and a week. Asking costs a message.