SHAPE CARAT TO MM SIZE CONVERSION CHART (ALSO CZ WT TO MM SIZE)

This chart is for purposes of estimating the mm size and/or carat weights for the more popular gemstone shapes.Actual sizes and weights will vary depending on the individual cut and material of each stone. As a general rule Cubic Zirconia will weigh approximately 70% more than its Diamond weight material.

(mm.)
CARAT DIA WT ROUND OVAL OCTAGON PEAR MARQUISE HEART SQUARE TRILLIANT
0.010 1.25
0.020 1.50
0.025 1.75 1.5 x 1.5
0.040 2.00 1.75 x 1.75
0.050 2.25 3 x 1.5 2 x 2
0.070 2.50 3.5 x 2.5 2.25 x 2.25
0.080 2.75 4 x 2 2.5 x 2.5
0.110 3.00 3 x 3 2.75 x 2.75 3 x 3
0.150 3.25 4 x 3 5 x 2.5 3 x 3
0.180 3.50 5 x 4 3.5 x 3.5 3.25 x 3.25
0.210 3.75 3.5 x 3.5
0.250 4.00 5 x 3 5 x 3 6 x 3 4 x 4 3.75 x 3.75 4 x 4
0.300 4.25 5 x 3 4 x 4
0.360 4.50 5.5 x 3.5 5.5 x 3 4.5 x 4.5 4.25 x 4.25 4.5 x 4.5
0.400 4.75 5.5 x 3.5 7 x 3.5 4.5 x 4.5 5 x 5
0.500 5.00 6 x 4 6 x 4 5 x 5 4.75 x 4.75 5.5 x 5.5
0.550 5.25 6 x 4 8 x 4 5 x 5 6 x 6
0.750 5.75 7 x 5 6.5 x 4.5 7 x 5 9 x 4.5 6 x 6 5.5 x 5.5 6.5 x 6.5
1.000 6.50 7.5 x 5.5 7 x 5 8 x 5 10 x 5 6.5 x 6.5 6 x 6 7 x 7
1.250 6.75 8 x 6 7.5 x 5.5 9 x 6 6.5 x 6.5 7.5 x 7.5
1.500 7.00 8.5 x 6.5 8 x 6 9.6 x 6.5 11 x 5.5 7 x 7 7 x 7 8 x 8
2.000 8.00 9 x 7 8.5 x 6.5 10 x 7 12 x 6 8 x 8 7.5 x 7.5 8.5 x 8.5
2.500 8.50 9.5 x 7.5 9 x 6.5 11 x 7 13 x 6.5 8.5 x 8.5 8 x 8 9 x 9
3.000 9.00 10 x 8 9 x 7 12 x 8 14 x 7 9 x 9 8.5 x 8.5 10 x 10
3.500 9.50 11 x 9 10 x 8 13 x 8 15 x 7.5 9.5 x 9.5 9 x 9 10.5 x 10.5
4.000 10.00 11.5 x 9.5 11 x 9 14 x 9 16 x 8 10 x 10 9.5 x 9.5 11 x 11
5.000 11.00 12 x 10 12 x 10 15 x 10 18 x 9 11 x 11 10 x 10 11.5 x 11.5
6.000 12.00 13 x 10 16 x 10 19 x 10 12 x 12 10.5 x 10.5 12 x 12
7.000 12.50 14 x 10 13 x 10 17 x 10
8.000 13.00 14 x 12 13.5 x 10.5 17 x 12 20 x 10 11 x 11 12.5 x 12.5
9.000 13.50 14 x 10 18 x 11 21 x 10 13 x 13
10.000 14.00 16 x 12 18 x 13 22 x 11 14 x 14 13 x 13
12.000 15.00 18 x 13 14 x 12 19 x 12 24 x 12 15 x 15 14 x 14
15.000 16.00 16 x 12 23 x 14 24 x 14 15.5 x 15.5 15 x 15
18.000 17.00 20 x 15 24 x 15 25 x 13 16 x 16 16 x 16
20.000 18.00 18 x 13 24 x 16 26 x 13 17 x 17 17 x 17
30.000 20.00 22 x 16 20 x 15 25 x 18 25 x 18 20 x 20 21 x 21
40.000 22.00 23 x 19 22 x 16 27 x 18 21 x 21 22 x 22
60.000 23.00 25 X 18 24 x 17 28 x 19 22 x 22 23 x 23