Diamond Size Chart

Diamonds can be measured in both carat weight and millimeter. While diamonds are purchased based on carat weight — the standard unit of measurement for loose diamonds — it’s important to consider millimeter measurements and ratios to choose the best possible option for your budget.

Round Cut Diamond Size Chart (MM)

Wondering what a 1 carat round diamond looks link on a hand? Our round diamond size chart will help you convert millimeter (mm) size to carat size for round cut diamonds.

Round Diamond Sizes

Round MM Size Round Carat Weight
0.8 mm. 0.0025 ct.
1 mm. 0.005 ct.
1.1 mm. 0.0067 ct.
1.2 mm. 0.009 ct.
1.25 mm. 0.01 ct.
1.3 mm. 0.01 ct.
1.5 mm. 0.015 ct.
1.75 mm. 0.02 ct.
1.8 mm. 0.025 ct.
2 mm. 0.03 ct.
2.2 mm. 0.04 ct.
2.5 mm. 0.06 ct.
2.75 mm. 0.08 ct.
3 mm. 0.10 ct.
3.25 mm. 0.14 ct.
3.5 mm. 0.17 ct.
3.75 mm. 0.21 ct.
4 mm. 0.25 ct.
4.25 mm. 0.28 ct.
4.5 mm. 0.36 ct.
4.75 mm. 0.44 ct.
5.0 mm. 0.50 ct.
5.25 mm. 0.56 ct.
5.5 mm. 0.66 ct.
5.75 mm. 0.75 ct.
6 mm. 0.84 ct.
6.25 mm. 0.93 ct.
6.5 mm. 1.00 ct.
6.8 mm. 1.25 ct.
Round MM Size Round Carat Weight
7 mm. 1.30 ct.
7.3 mm. 1.50 ct.
7.5 mm. 1.67 ct.
7.75 mm. 1.75 ct.
8 mm. 2.00 ct.
8.25 mm. 2.11 ct.
8.5 mm. 2.43 ct.
8.7 mm. 2.50 ct.
9 mm. 2.75 ct.
9.1 mm. 3.00 ct.
9.5 mm. 3.35 ct.
9.75 mm. 3.61 ct.
10 mm. 3.87 ct.
10.25 mm. 4.16 ct.
10.5 mm. 4.41 ct.
10.75 mm. 4.57 ct.
11 mm. 4.91 ct.
11.25 mm. 5.49 ct.
11.5 mm. 5.85 ct.
12 mm. 6.84 ct.
12.25 mm. 7.26 ct.
12.5 mm. 7.36 ct.
12.75 mm. 7.52 ct.
13 mm. 8.51 ct.
13.5 mm. 9.53 ct.
14 mm. 10.49 ct.
15 mm. 12.89 ct.
16 mm. 16.06 ct.

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