What size diamond should I get? Pick by ring size and look

By HeyGema™ · Updated

In short

On a size 6 finger a classic round diamond is 0.45 to 1.53 carat and a bold one 1.53 to 3.62 carat. Pick your ring size, shape and look in the tool, then copy the result as a message for your jeweler.

What size diamond should I get

Skin tone
6.2 mm
6.2 mm stone on a 16.5 mm finger: it covers 38% of the width0.9 carat round on a size 6 finger.

A classic look on a size 6 finger: about 0.9 carat, 6.2 mm.

Hi, I would like a round diamond of about 0.9 carat (6.2 mm) for a size 6 ring. It covers about 38% of the width of the finger, a classic look.

Round diamond carat range by ring size

For each ring size, the carat weight of a round diamond that gives each look. The four looks are our own bands for the share of the finger's width a stone covers: delicate under 30% of the finger's width; classic 30% to 44%; bold 45% to 59%; statement 60% and more. They are a way to read the numbers, not a rule.

Size 4
Finger width: 14.9 mm
Delicate: up to 0.33 ct
Classic: 0.33 to 1.12 ct
Bold: 1.12 to 2.65 ct
Statement: 2.65 and up ct
Size 5
Finger width: 15.7 mm
Delicate: up to 0.39 ct
Classic: 0.39 to 1.31 ct
Bold: 1.31 to 3.11 ct
Statement: 3.11 and up ct
Size 6
Finger width: 16.5 mm
Delicate: up to 0.45 ct
Classic: 0.45 to 1.53 ct
Bold: 1.53 to 3.62 ct
Statement: 3.62 and up ct
Size 7
Finger width: 17.3 mm
Delicate: up to 0.52 ct
Classic: 0.52 to 1.76 ct
Bold: 1.76 to 4.18 ct
Statement: 4.18 and up ct
Size 8
Finger width: 18.1 mm
Delicate: up to 0.6 ct
Classic: 0.6 to 2.02 ct
Bold: 2.02 to 4.8 ct
Statement: 4.8 and up ct
Size 9
Finger width: 18.9 mm
Delicate: up to 0.68 ct
Classic: 0.68 to 2.31 ct
Bold: 2.31 to 5.47 ct
Statement: 5.47 and up ct

How to choose a diamond size

  1. 1

    Find the ring size

    Use a ring the person already wears, or a strip of paper around the finger. The ring size chart in mm turns a measurement into a size.

  2. 2

    Choose how much of the finger the stone covers

    Delicate is under a third, classic is a third to just under half, bold is about half to three fifths, and statement is more.

  3. 3

    Pick a shape

    A long shape such as an oval or an emerald cut has more face-up area than a round of the same weight, so it needs less carat weight to look the same size.

  4. 4

    Read the carat weight and the millimeters

    The tool shows both and draws the stone on the finger.

  5. 5

    Send both to your jeweler

    Millimeters tell them exactly how big, since two stones of one weight can differ in width.

Weight is not the only thing that sets size

Two diamonds of the same carat weight can differ in width because of their cut: a deep stone is smaller across. The setting also changes the look, since a thin band and small prongs make a stone read larger and a halo adds width. When it matters, ask for the millimeter measurements of the stone along with its weight. The tell your jeweler guide shows what to say.

Questions

It depends on the finger and the look you like. On a size 6 finger a round diamond of 0.45 to 1.53 carat gives a classic look and 1.53 to 3.62 carat a bold one. Use the tool above for your ring size and shape.
Start from the ring size, choose how much of the finger the stone should cover, then read the carat weight for your shape. Check the millimeter size too, because stones of one weight differ in width.
A round 1 carat is 6.5 mm across: 39% of the width of a size 6 finger, a classic look. Whether it is enough is a matter of taste; the tool shows it on your ring size.
Long shapes. For the same weight an oval, pear, marquise or emerald cut faces up larger than a round. See which shapes look biggest.

More size charts