convertimate Diamond carat to mm

Grams to carats

Type a value in g to get it in ct instantly.

2.5ct

That's 1.08× as big as a two-carat diamond, while a five-carat diamond is 1.26× bigger. A well-cut round brilliant 8.759 mm across weighs about 2.5 ct.

What it means

How big is that stone?

For well-cut round brilliants. Deep stones weigh more for their spread and shallow ones less; other shapes and gems differ.

The math

How to convert g to ct

For a round brilliant: carats ≈ 0.00372 × diameter³ (diameter in mm), so diameter ≈ ∛(carats ÷ 0.00372).

Example: 0.5 g = 2.5 ct.

Every unit

That diamond in every unit

Tables

g to ct conversion table

g to ct conversion table
gct
0.1 g0.5 ct
0.2 g1 ct
0.25 g1.25 ct
0.3 g1.5 ct
0.4 g2 ct
0.5 g2.5 ct
0.75 g3.75 ct
1 g5 ct
1.25 g6.25 ct
1.5 g7.5 ct
2 g10 ct
2.5 g12.5 ct
3 g15 ct
4 g20 ct
5 g25 ct
ct to g conversion table
ct to g conversion table
ctg
0.1 ct0.02 g
0.2 ct0.04 g
0.25 ct0.05 g
0.3 ct0.06 g
0.4 ct0.08 g
0.5 ct0.1 g
0.75 ct0.15 g
1 ct0.2 g
1.25 ct0.25 g
1.5 ct0.3 g
2 ct0.4 g
2.5 ct0.5 g
3 ct0.6 g
4 ct0.8 g
5 ct1 g

Quick answers

Quick answers

How many ct is 1 g?
1 g is 5 ct.
How many ct is 10 g?
10 g is 50 ct.
How many ct is 0.5 g?
0.5 g is 2.5 ct.

The units

About these units

Grams (g)

The weight of the stone in grams.

Carats (ct)

The weight of the stone: 0.2 g per carat.

Learn more about diamond units

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