How to measure your ring size at home

How do you measure your ring size at home?

Measure a ring that already fits the finger the new ring is for. Lay it flat on a ruler and measure straight across the inside, edge to edge through the centre, in millimetres. That inside diameter is the size: read it against the UK chart and you have a letter.

Use a round ring that fits the same finger on the same hand. GIA notes that the inside of the ring must be perfectly round for this to work, so a ring that has been knocked out of shape is one for a jeweller to measure.

Read the ruler as closely as you can. A whole UK letter is only about 0.4mm across the inside and the marks on a ruler are a millimetre apart, so measure two or three times and judge the reading between the marks.

A ring is the better of the two home methods, because it already shows how it passes the knuckle. Our ring size finder takes the measurement, asks about the band width and the knuckle and tells you what to check for each.

Ring size finder: Find a UK size from a ring you own or a paper strip.

Finding a ring size secretly: Measuring for someone else without giving the surprise away.

How do you measure ring size with string or paper?

Wrap a strip of paper snugly around the base of the finger, mark where it meets, then lay it flat and measure to the mark in millimetres. That length is the inside circumference of the ring. Do not pull the strip tight.

String works the same way. GIA points out that string can stretch and paper is easily damaged, so treat either reading as an estimate.

A strip around the base of the finger also says nothing about the knuckle, so check that a ring of that size would pass over it. Use the strip when there is no ring to measure. If you can, check the result against a ring that fits before you order.

How do you turn millimetres into a UK ring size?

Match your measurement to the nearest row of a size chart. From a ring you have the inside diameter and from a strip you have the circumference. To move between the two, multiply the diameter by pi (3.14): a ring 17.25mm across is 54.2mm around, which is a UK N.

These are the measurements our rings are made to, each with its nearest US size. UK L is 16.5mm across the inside and 51.8mm around (US 6). UK N is 17.25mm across and 54.2mm around (US 7). UK P is 17.99mm across and 56.5mm around (US 7.75). UK R is 18.8mm across and 59.1mm around (US 8.75). UK T is 19.6mm across and 61.6mm around (US 9.75). UK V is 20.35mm across and 63.9mm around (US 10.75). UK X is 21.1mm across and 66.3mm around (US 11.75).

UK sizes go up in half letters. Each half size adds about 0.6mm to the circumference, which is about 0.2mm across. Roughly two UK letters make one US size. A European size is the inside circumference to the nearest millimetre, so a UK N is a European 54.

A chart gives the nearest match, so keep the millimetres beside the letter when you order. Our ring size converter looks up a UK or US size, or a circumference in millimetres, on the same chart.

Ring size converter: Every row from UK F to Z1, with half sizes, in millimetres.

UK ring size L: US 6 and European 52, with the half sizes either side.

UK ring size N: US 7 and European 54, with the half sizes either side.

UK ring size P: US 7.75 and European 57, with the half sizes either side.

UK ring size R: US 8.75 and European 59, with the half sizes either side.

UK ring size T: US 9.75 and European 62, with the half sizes either side.

UK ring size V: US 10.75 and European 64, with the half sizes either side.

UK ring size X: US 11.75 and European 66, with the half sizes either side.

What should you do if you are between two ring sizes?

Choose the half size between them. A ring that is close but not right is usually a half size out, not a whole one. Our titanium, zirconium and inlay bands are made to order in every half size from A to Z, then on to Z+10. Our solid gold bands are made in whole sizes from A to Z.

If the choice is between two whole letters, measure again on a different day and choose by how a ring feels across the readings. On a band 6mm or wider, the larger of the two is the usual choice.

The metal matters too. A plain gold band can be made larger or smaller by a jeweller later. Titanium can often be made a little larger, though never smaller. Black zirconium is made to size, so settle the size before you order.

Still not sure? Choose I do not know yet on the ring's page. We confirm the size with you before anything is made.

Which rings can be resized: Resizing, metal by metal.

Returns: What happens if a ring arrives the wrong size.

Does a wide band need a bigger ring size?

Often, by about half a size. A wide band covers more of the finger, so it feels snugger than a narrow ring at the same size.

Our size finder treats 6mm or wider as a wide band. It adds nothing to the result automatically. It asks you to check the fit with a ring of a comparable width and inside profile, because fit cannot be worked out from a fixed allowance.

So measure with a ring about as wide as the one you are buying. If you land on a clean size, keep it. If you fall between two letters, the larger is the usual choice. A court profile, curved on the inside, also passes over the knuckle more easily than a flat inside.

Band width guide: Every width side by side, with how each fits.

6mm or 8mm?: How the two widths compare on the hand.

How do you measure a man's ring size with a large knuckle?

Size for both the knuckle and the base of the finger. The ring has to slide over the knuckle with a little resistance and still sit securely at the base without spinning. A ring that already fits has passed that test, so measure one if you can.

A paper strip around the base cannot establish that fit on its own. For most people the joint is larger than the rest of the finger, so a size read from the base alone can give a ring that will not go on.

Men's sizes are measured the same way as anyone's: the UK letters are one scale. Two things matter more on a man's ring. Men's bands are often 6mm or wider, so the wide band check applies. The dominant hand is usually about half a size larger, so measure the finger the ring will be worn on.

Never worn a ring? Take the strip measurement as a start, then have the finger checked with a jeweller's ring sizer, or order with I do not know yet.

How should a wedding ring fit?: Snug but not tight and how to tell.

Wedding rings in large sizes: Size Z and above, made to order.

When is the best time of day to measure your ring size?

When your hands are at an ordinary room temperature, neither cold nor hot. Fingers shrink in the cold and swell in the heat, so a reading taken on a cool morning can differ from one taken in the afternoon. Humidity and flying change them too.

Measure twice, on different days. Then choose by how a ring feels across the readings instead of automatically picking the largest. A ring that fits well is slightly loose when you are cold and slightly snug when you are warm.