Imperial Facets

Comprehensive Diamond Size Correlation Data

Explore detailed tables that correlate diamond sieve sizes with pieces per carat, average carat weight, and diameter measurements for precise evaluation.

Pieces per Carat (PCs/Ct)	Sieve Size (Plate No.)	Avg. Weight (Carat)	Diameter (mm)
1/333	+0000 to -000	0.002	0.80-0.90
1/250	+000 to -00	0.004	0.90-1.00
1/200	+00 to -0	0.005	1.00-1.10
1/175	+0 to -1	0.006	1.10-1.15
1/150	+1 to -1.5	0.007	1.15-1.20
1/120	+1.5 to -2	0.008	1.20-1.25
1/100	+2 to -2.5	0.009	1.25-1.30
	+2.5 to -3	0.010	1.30-1.35
	+3 to -3.5	0.011	1.35-1.40
1/80	+3.5 to -4	0.012	1.40-1.45
	+4 to -4.5	0.013	1.45-1.50
1/70	+4.5 to -5	0.014	1.50-1.55
1/60	+5 to -5.5	0.016	1.55-1.60
1/50	+5.5 to -6	0.018	1.60-1.70
	+6 to -6.5	0.021	1.70-1.80
1/40	+6.5 to -7	0.025	1.80-1.90
1/30	+7 to -7.5	0.029	1.90-2.00
	+7.5 to -8	0.035	2.00-2.10
1/25	+8 to -8.5	0.039	2.10-2.20
	+8.5 to -9	0.044	2.20-2.30
1/20	+9 to -9.5	0.052	2.30-2.40
	+9.5 to -10	0.058	2.40-2.50
1/15	+10 to -10.5	0.069	2.50-2.60
	+10.5 to -11	0.074	2.60-2.70
1/12	+11 to -11.5	0.078	2.70-2.80
	+11.5 to -12	0.086	2.80-2.90
1/10	+12 to -12.5	0.095	2.90-3.00
	+12.5 to -13	0.108	3.00-3.10
1/8	+13 to -13.5	0.116	3.10-3.20
	+13.5 to -14	0.125	3.20-3.30
1/7	+14 to -14.5	0.135	3.30-3.40
	+14.5 to -15	0.146	3.40-3.50
1/6	+15 to -15.5	0.159	3.50-3.60
	+15.5 to -16	0.175	3.60-3.70
	+16.5 to -18	~0.20	~3.80
	+18	~0.25	~4.10

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Approximate Carat Weight to Millimeter Conversion Charts by Shape

The following tables provide the approximate carat weight for various diamond shapes based on their millimeter dimensions.

Round Brilliant Cut

Diameter (mm)	Approx. Carat Weight
0.80	0.002
1.00	0.01
1.25	0.01
1.50	0.02
1.75	0.02
2.00	0.03
2.25	0.05
2.50	0.06
2.75	0.08
3.00	0.11
3.25	0.14
3.50	0.17
3.75	0.21
4.00	0.25
4.50	0.36
5.00	0.49
5.25	0.56
5.50	0.66
6.00	0.84
6.50	1.03
7.00	1.28
7.50	1.67
8.00	2.04
8.50	2.43
9.00	2.75
9.50	3.35
10.00	3.87

Fancy Shapes

Shape	Dimensions (L x W mm)	Approx. Carat Weight
Baguette	2.00 x 1.50	0.040
	2.50 x 1.50	0.05
	3.00 x 2.00	0.10
	3.50 x 2.00	0.11
	4.00 x 2.00	0.13
	4.50 x 2.50	0.22
	5.00 x 3.00	0.35
	6.00 x 3.00	0.42
Emerald	3.00 x 2.00	0.08
	4.00 x 3.00	0.25
	5.00 x 3.00	0.33
	5.50 x 4.00	0.62
	6.00 x 4.00	0.69
	7.00 x 5.00	1.06
	8.00 x 6.00	1.74
	9.00 x 7.00	2.62
	10.00 x 8.00	4.38
Marquise	3.00 x 1.50	0.03
	4.00 x 2.00	0.07
	5.00 x 2.50	0.12
	6.00 x 3.00	0.21
	7.00 x 3.50	0.33
	8.00 x 4.00	0.50
	9.00 x 4.50	0.71
	10.00 x 5.00	0.95
	11.00 x 5.50	1.25
Pear	3.00 x 2.00	0.05
	4.00 x 2.50	0.10
	5.00 x 3.00	0.17
	6.00 x 4.00	0.37
	7.00 x 5.00	0.68
	8.00 x 5.00	0.81
	9.00 x 6.00	1.33
	10.00 x 7.00	1.95
	12.00 x 8.00	3.00
Oval	3.00 x 2.00	0.05
	4.00 x 3.00	0.13
	5.00 x 3.50	0.25
	6.00 x 4.00	0.37
	7.00 x 5.00	0.68
	8.00 x 6.00	1.12
	9.00 x 7.00	1.86
	10.00 x 8.00	2.54
	12.00 x 10.00	5.05
Radiant	3.00 x 3.00	0.15
	4.00 x 4.00	0.43
	5.00 x 4.00	0.61
	6.00 x 5.00	0.96
	7.00 x 5.00	1.14
	8.00 x 6.00	1.74
	9.00 x 7.00	2.62
	10.00 x 8.00	3.49

Square & Triangular Shapes

Shape	Dimensions (mm)	Approx. Carat Weight
Princess	1.50	0.02
	2.00	0.047
	2.50	0.092
	3.00	0.159
	3.50	0.25
	4.00	0.377
	4.50	0.537
	5.00	0.71
	5.50	0.99
	6.00	1.24
	6.50	1.59
	7.00	1.96
	8.00	3.01
	9.00	4.12
	10.00	5.62
Cushion	2.50	0.10
	3.00	0.16
	3.60	0.25
	4.00	0.36
	4.50	0.50
	5.00	0.71
	5.50	0.94
	6.00	1.09
	6.50	1.25
	7.00	2.00
	8.00	3.01
	9.00	4.30
	10.00	5.90
Trillion	3.00	0.09
	3.50	0.14
	4.00	0.21
	4.50	0.30
	5.00	0.41
	5.50	0.55
	6.00	0.70
	6.50	0.91
	7.00	1.10
	8.00	1.75
	9.00	2.35