How many carats is a 13 mm diamond?

By HeyGema™ · Updated

In short

A 13 mm round diamond weighs about 8.19 carat (1.64 grams). A 13 mm princess cut weighs about 13.21 carat, and an oval that is 13 mm long about 4.31 carat.

Carat to mm calculator

About 8.19 carat

An estimate for a well-cut stone. A deep or shallow cut faces up smaller or bigger.

13 mm diamond weight by shape

The weight of a well-cut diamond measuring 13 mm. For round and square shapes the number is the diameter or the side. For longer shapes it is the long side, with the width following the usual ratio.

Round
Size: 13 mm
Weight: 8.19 ct
Oval
Size: 13 mm x 9.0 mm
Weight: 4.31 ct
Cushion
Size: 13 mm x 13.0 mm
Weight: 12.51 ct
Princess
Size: 13 mm x 13.0 mm
Weight: 13.21 ct
Emerald cut
Size: 13 mm x 9.3 mm
Weight: 6.41 ct
Asscher
Size: 13 mm x 13.0 mm
Weight: 13.21 ct
Radiant
Size: 13 mm x 10.0 mm
Weight: 8 ct
Pear
Size: 13 mm x 8.4 mm
Weight: 3.56 ct
Marquise
Size: 13 mm x 6.5 mm
Weight: 1.95 ct
Heart
Size: 13 mm x 13.0 mm
Weight: 8 ct
Trillion
Size: 13 mm x 13.0 mm
Weight: 6.41 ct
Baguette
Size: 13 mm x 6.5 mm
Weight: 4.29 ct

13 mm stones in other gems

A round stone of the same size weighs differently in each gem, because gems differ in density.

Diamond
Weight of a round stone: 8.19 ct
Moissanite
Weight of a round stone: 7.49 ct
Sapphire
Weight of a round stone: 9.3 ct
Ruby
Weight of a round stone: 9.3 ct
Emerald
Weight of a round stone: 6.33 ct
Aquamarine
Weight of a round stone: 6.28 ct
Topaz
Weight of a round stone: 8.21 ct
Amethyst
Weight of a round stone: 6.16 ct
Spinel
Weight of a round stone: 8.37 ct
Tanzanite
Weight of a round stone: 7.79 ct
Morganite
Weight of a round stone: 6.51 ct

13 mm diamond studs

A pair of 13 mm round diamond studs has a total carat weight of about 16.37 carat, 8.19 carat for each stone. See the diamond stud earring size chart.

Nearby sizes

11 mm
Weight: 4.96 ct
Inches: 0.43 in
12 mm
Weight: 6.44 ct
Inches: 0.47 in
13 mm (this page)
Weight: 8.19 ct
Inches: 0.51 in
14 mm
Weight: 10.23 ct
Inches: 0.55 in
15 mm
Weight: 12.58 ct
Inches: 0.59 in

Questions

About 8.19 carat for a well-cut round diamond.
A 13 mm princess cut, measured along one side, weighs about 13.21 carat.
A 13 mm round moissanite is labeled 8.19 carat (diamond equivalent weight) and weighs about 7.49 carat. See the moissanite size chart.
13 mm is 0.51 inches.

More size charts