Ring size guide.

A ring that fits slides on with light pressure and needs a gentle tug to come back over the knuckle. If it spins freely it is too large. If it leaves a mark it is too small.

Every piece is made to order in the size you give us, so it is worth two minutes now.

We make US sizes 3 to 9, including half sizes. The chart below runs to US 13 so you can identify any size. If yours falls outside 3 to 9, write to us before you order and we will arrange it.

Measure the finger

Cut a strip of paper about 5 mm wide, or take a length of string.

Wrap it around the base of the finger, snug but not tight, and mark where it overlaps.

Lay it flat against a ruler and read the length in millimeters. That is the circumference. Find it in the chart below.

Or measure a ring that already fits

Take a ring worn on the same finger. Measure straight across the inside, edge to edge, in millimeters. That is the diameter. Find it in the chart below.

The chart

US size · inside diameter · inside circumference

US 4 · 14.9 mm · 46.8 mm
US 4.5 · 15.3 mm · 48.1 mm
US 5 · 15.7 mm · 49.3 mm
US 5.5 · 16.1 mm · 50.6 mm
US 6 · 16.5 mm · 51.8 mm
US 6.5 · 16.9 mm · 53.1 mm
US 7 · 17.3 mm · 54.3 mm
US 7.5 · 17.7 mm · 55.6 mm
US 8 · 18.1 mm · 56.9 mm
US 8.5 · 18.5 mm · 58.1 mm
US 9 · 18.9 mm · 59.4 mm
US 9.5 · 19.4 mm · 60.9 mm
US 10 · 19.8 mm · 62.2 mm
US 10.5 · 20.2 mm · 63.5 mm
US 11 · 20.6 mm · 64.7 mm
US 11.5 · 21.0 mm · 66.0 mm
US 12 · 21.4 mm · 67.2 mm
US 12.5 · 21.8 mm · 68.5 mm
US 13 · 22.2 mm · 69.7 mm

What changes the answer

Fingers are widest at the end of the day and in warm weather, narrowest first thing and in the cold. Measure in the afternoon, at normal room temperature.

A prominent knuckle means the ring has to pass a wider point than it will sit on. Measure the knuckle too and take the size between the two.

Wide bands sit tighter than narrow ones. For a band of 6 mm or more, go up a half size.

Measure the exact finger the ring is for. The two hands are rarely the same.

Buying as a surprise

Borrow a ring they already wear on the right finger and measure the inside diameter. If that is not possible, write to us before you order and we will talk it through.

How to send us your size

Choose your carat, gold and color on the product page, then send the size straight after you order. Reply to your order confirmation with the ring size, or write to info@rivamoissanite.com with your order number.

We do not start the ring until we have your size, so nothing is lost by taking a day to measure properly.

If the size is still not right

Write to us and we will tell you whether the piece can be resized and what it will cost. Resizing is quoted case by case and carried out at your cost. Some settings cannot be resized without remaking the piece, and we will tell you if yours is one of them.