Carat to milligram converter: 1 carat is 200 mg

By HeyGema™ · Updated November 5, 2026

In short

1 carat = 200 milligrams. 1 milligram = 0.005 carats. The carat is exactly 200 milligrams (0.2 grams).

AmountFromTo

1 carats = 200 milligrams

1 carat is exactly 200 milligrams (0.2 grams). A point is one hundredth of a carat.

Carats to milligrams

A carat is exactly 200 mg, set by international agreement in 1907. A point is one hundredth of a carat, 2 mg.

For a sense of scale, this is what common round diamond weights come to in grams and milligrams, and how wide each stone is.

0.25 ct: In grams: 0.050 g; In milligrams: 50 mg; Round diamond size: 4.1 mm

10 ct: In grams: 2.00 g; In milligrams: 2000 mg; Round diamond size: 13.9 mm

Weight	In grams	In milligrams	Round diamond size
0.25 ct	0.050 g	50 mg	4.1 mm
0.5 ct	0.10 g	100 mg	5.1 mm
1 ct	0.20 g	200 mg	6.5 mm
2 ct	0.40 g	400 mg	8.1 mm
3 ct	0.60 g	600 mg	9.3 mm
5 ct	1.00 g	1000 mg	11.0 mm
10 ct	2.00 g	2000 mg	13.9 mm

1 milligram = 0.005 carats. For all weight units at once use the carat converter. For size instead of weight, see the carat to mm calculator.

1 carat is exactly 200 milligrams.

100 milligrams.