Diamond size chart 

Here you find / check out full cut and polished diamonds actual millimeter sizes of the girdle diameter to their approximate weight.
These are the standard or ideal ct weight to girdle measurement sizes given below for an ideal cut stone but some factors which affects it away from accuracy may be the proportions like height, crown, culet, pavilion of the stone, its girdle is kept thick or thin the polishing and cutting even the inclusions makes sometimes minor differences. So the diamonds which are graded in cut as good fair or even below these standards then the measurement of weight and the carat weight wont verify or match with the given charts.

In any loose diamond pictures to understand the size always ask the seller to keep the diamonds on hand or with any known object of perfect known sizes like match box or inch measuring scale so to have a more definite and accurate idea of how the diamond will look in real life when set into a piece of jewelry like ring or earring.

So please check the mm to weight guide charts for some common shapes.

Round Brilliant cut
MM Size
Carat Weight
0.8 mm.
0.0025 ct.
1 mm.
0.005 ct.
1.15 mm.
0.0067 ct.
1.12 mm.
0.0075 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.
2.25 mm.
0.04 ct.
2.5 mm.
0.06 ct.
2.75 mm.
0.08 ct.
3 mm.
0.11 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.
MM Size
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.



Cushion cut shape
MM Size
Carat Weight
4.2 mm.
0.40 ct.
4.9 mm.
0.50 ct.
5.25 mm.
0.75 ct.
5.5 mm.
1.00 ct.
6 mm.
1.25 ct.
6.5 mm.
1.50 ct.
7 mm.
2.00 ct.
7.5 mm.
2.50 ct.
MM Size
Carat Weight
8 mm.
3.00 ct.
8.5 mm.
3.50 ct.
9 mm.
4.12 ct.
9.5 mm.
5.09 ct.
10 mm.
5.62 ct.
11 mm.
7.44 ct.
12 mm.
9.52 ct.
13 mm.
12.66 ct.





Pear Shape
MM Size
Carat Weight
3×2 mm.
0.13 ct.
4×2.5 mm.
0.18 ct.
4×3 mm.
0.21 ct.
5×3 mm.
0.25 ct.
5×4 mm.
0.35 ct.
6×4 mm.
0.50 ct.
6.5×4.5 mm.
0.60 ct.
7×5 mm.
0.75 ct.
7.5×5.5 mm.
0.85 ct.
7.7×5.7 mm.
1.00 ct.
8×6 mm.
1.25 ct.
8.5×6.5 mm.
1.50 ct.
10×6 mm.
1.71 ct.
8.7×6.7 mm.
1.80 ct.
9×7 mm.
2.00 ct.
10×8 mm.
2.50 ct.
11×7.50 mm.
2.61 ct.
13×8 mm.
2.98 ct.
11×8 mm.
3.00 ct.