Diamond Carat Size Chart

Compare approximate millimeter dimensions and carat weights across popular lab-grown diamond shapes. Select a shape below to explore its size-to-weight reference chart.

Carat measures a diamond's weight, while millimeters describe its physical dimensions. These tables provide approximate reference values, not exact conversions. Actual weight and measurements vary with cut proportions, depth, girdle, and the individual stone.

Learn more: Diamond Carat Guide · Lab-Grown Diamond Price Calculator

Reference note: Princess and Cushion size rows have been revised using published shape-specific measurements from ActualRingSizer. Other shapes retain their existing reference rows except for the Round and Marquise corrections. Published charts can differ because of cut proportions; verify the exact measurements and carat weight for an individual diamond.

  • Round
  • Princess
  • Asscher
  • Cushion
  • Oval
  • Radiant
  • Emerald
  • Pear
  • Heart
  • Marquise
  • Triangle
  • Kite / Trillion
  • Baguette
  • Tapered Baguette

Round Cut

Dimensions (mm) Approx. Carat Weight
0.8 0.0025
1 0.005
1.12 0.0067
1.15 0.0075
1.25 0.01
1.3 0.01
1.5 0.015
1.75 0.02
1.8 0.025
2 0.03
2.25 0.04
2.5 0.06
2.75 0.08
3 0.11
3.25 0.14
3.5 0.17
3.75 0.21
4 0.25
4.25 0.28
4.5 0.36
4.75 0.44
5 0.46
5.25 0.56
5.5 0.66
5.75 0.76
6 0.84
6.25 0.93
6.5 1.03
6.75 1.24
Dimensions (mm) Approx. Carat Weight
7 1.28
7.25 1.49
7.5 1.67
7.75 1.75
8 2.04
8.25 2.11
8.5 2.43
8.75 2.55
9 2.75
9.25 3.05
9.5 3.35
9.75 3.61
10 3.87
10.25 4.16
10.5 4.41
10.75 4.57
11 4.91
11.25 5.49
11.5 5.85
12 6.84
12.25 7.26
12.5 7.36
12.75 7.52
13 8.51
13.5 9.53
14 10.49
15 12.89
16 16.06

Shop Round Cut

Princess / Square Cut

Size (mm) Approx. Carat Weight
3.46 0.25
4.37 0.50
5.00 0.75
5.50 1.00
5.92 1.25
6.30 1.50
Size (mm) Approx. Carat Weight
6.63 1.75
6.93 2.00
7.46 2.50
7.93 3.00
8.73 4.00
9.40 5.00

Shop Princess Cut

Asscher Cut

Dimensions (mm) Approx. Carat Weight
4 0.39
4.5 0.56
5 0.71
5.5 0.99
6 1.24
6.5 1.59
7 1.96
7.5 2.4
Dimensions (mm) Approx. Carat Weight
8 3.01
8.5 3.67
9 4.12
9.5 5.09
10 5.62
11 7.44
12 9.52
13 12.66

Shop Asscher Cut

Cushion Cut

Size (mm) Approx. Carat Weight
3.78 0.25
4.76 0.50
5.45 0.75
6.00 1.00
6.46 1.25
6.87 1.50
Size (mm) Approx. Carat Weight
7.23 1.75
7.56 2.00
8.14 2.50
8.65 3.00
9.52 4.00
10.26 5.00

Shop Cushion Cut

Oval Cut

Dimensions (mm) Approx. Carat Weight
4.5 x 3.5 0.21
5 x 3 0.21
5 x 4 0.35
5.5 x 3.5 0.33
6 x 4 0.43
6.5 x 4.5 0.65
6 x 5 0.61
7 x 5 0.76
7.5 x 5.5 0.98
8 x 6 1.21
8.5 x 6.5 1.46
9 x 6 1.41
9 x 7 1.86
Dimensions (mm) Approx. Carat Weight
10 x 8 2.54
10.5 x 8.5 2.88
11 x 9 3.85
12 x 8 2.99
12 x 10 5.05
14 x 10 5.81
13 x 11 6.05
14 x 12 8.21
15 x 12 8.76
16 x 12 9.32
16 x 14 11.88
18 x 13 12.86
20 x 15 14.96

Shop Oval Cut

Radiant Cut

Dimensions (mm) Approx. Carat Weight
4.5 x 3.5 0.34
5 x 3 0.31
6 x 3 0.41
6 x 4 .60
6.5 x 4.5 0.83
7 x 5 1.14
7.25 x 5.25 1.24
7.5 x 5.5 1.47
8 x 6 1.74
8.5 x 6.5 2.25
9 x 7 2.62
9.5 x 7.5 3.18
10 x 7 3.31
Dimensions (mm) Approx. Carat Weight
10 x 8 3.49
11 x 9 5.05
11.5 x 10 6.45
12 x 9 6.06
12 x 10 6.79
13 x 9 6.54
13 x 11 9.33
13.5 x 11.5 10.19
14 x 10 8.47
14 x 12 12.14
15 x 11 11.48
16 x 12 14.22

Shop Radiant Cut

Emerald Cut

Dimensions (mm) Approx. Carat Weight
3 x 2 0.1
3.5 x 2 0.12
4 x 2 0.15
4 x 3 0.2
5 x 3 0.29
5.5 x 3.5 0.46
5.5 x 4 0.48
6 x 4 0.66
6.5 x 4.5 0.88
7 x 5 1.06
7.25 x 5.25 1.24
7.5 x 5.5 1.45
8 x 6 1.74
8.5 x 6.5 2.17
Dimensions (mm) Approx. Carat Weight
9 x 7 2.62
9.5 x 7.5 3.21
10 x 7 3.01
10 x 8 3.79
11 x 9 5.21
12 x 8 5.34
12 x 10 6
13 x 9 6.38
14 x 8 6.25
14 x 10 8.48
13 x 11 9.13
14 x 12 11.26
16 x 12 14.22

Shop Emerald Cut

Pear Cut

Dimensions (mm) Approx. Carat Weight
3 x 2 0.13
4 x 2.5 0.18
4 x 3 0.21
5 x 3 0.25
5 x 4 0.35
6 x 4 0.39
6.5 x 4.5 0.57
7 x 5 0.71
8 x 5 0.81
8.5 x 5.5 1.08
8 x 6 1.25
9 x 6 1.33
9 x 7 1.75
10 x 6 1.71
10 x 7 1.8
10 x 8 2.46
11 x 7.50 2.61
11 x 8 3
12 x 7 3.12
Dimensions (mm) Approx. Carat Weight
12 x 8 3
12 x 9 3.44
13 x 8 2.98
14 x 8 3.47
13 x 9 4.11
14 x 9 4.25
15 x 9 5.06
14 x 10 5.41
13 x 11 5.65
15 x 10 5.75
15 x 11 7.36
16 x 9 5.86
16 x 10 6.27
16 x 12 8.99
17 x 10 6.46
18 x 11 8.14
18 x 12 9.35
18 x 13 10.21

Shop Pear Cut

Heart Cut

Dimensions (mm) Approx. Carat Weight
3.5 0.18
4 0.25
4.25 0.28
4.5 0.34
4.75 0.38
5 0.44
5.5 0.61
6 0.74
6.25 0.83
6.5 0.93
7 1.13
7.5 1.59
Dimensions (mm) Approx. Carat Weight
8 1.71
9 2.41
9.5 2.9
10 3.16
11 4.41
12 5.66
13 7.88
14 9.38
15 10.79
16 13.27
18 15.33

Shop Heart Cut

Marquise Cut

Dimensions (mm) Approx. Carat Weight
3 x 1.5 0.025
3.5 x 1.75 0.065
3.5 x 2 0.07
3.75 x 1.75 0.11
4 x 2 0.1
4.25 x 2.25 0.12
5 x 2.5 0.14
5 x 3 0.2
5.5 x 2.75 0.16
5.5 x 3 0.18
6 x 3 0.25
6.5 x 3 0.23
7 x 3 0.3
7 x 3.5 .35
7 x 4 0.34
7.5 x 3.5 0.33
8 x 4 0.47
9 x 4.5 0.71
Dimensions (mm) Approx. Carat Weight
9 x 5 0.76
9.5 x 5 0.85
10 x 5 0.95
11 x 5.5 1.25
11.5 x 6 1.33
12 x 6 1.62
12 x 6.5 1.71
13 x 6.5 2.11
14 x 7 2.48
15 x 7.5 3.09
14 x 8 3
15 x 7 3.12
15 x 8 3.44
16 x 8 3.86
17 x 8.5 4.88
17.5 x 10 5.5
20 x 8 7.08
20 x 10 7.94
20 x 11 9.5

Shop Marquise Cut

Triangle Cut

Dimensions (mm) Approx. Carat Weight
2.5 0.08
3 0.12
3.5 0.18
4 0.25
4.25 0.32
4.5 0.37
4.75 0.42
5 0.45
5.25 0.53
5.5 0.66
5.75 0.71
6 0.76
6.25 0.86
6.5 0.94
6.75 1.02
Dimensions (mm) Approx. Carat Weight
7 1.11
7.25 1.32
7.5 1.45
7.75 1.69
8 1.79
8.25 1.86
9 2.15
9.25 2.54
9.75 3.25
10 3.52
11 4.74
12 6.03
13 8.12
14 9.83

Shop Triangle Cut

Kite / Trillion Cut

Dimensions (mm) Approx. Carat Weight
3 0.12
3.5 0.16
3.75 0.19
4 0.23
4.25 0.27
4.5 0.31
4.75 0.37
5 0.42
5.25 0.49
5.5 0.55
5.75 0.64
6 0.7
Dimensions (mm) Approx. Carat Weight
6.25 0.75
6.5 0.91
6.75 0.98
7 1.1
7.5 1.21
8 1.75
9 2.35
11 3.66
12 4.9
13 6.42
15 9

Shop Kite / Trillion Cut

Baguette Straight Cut

Dimensions (mm) Approx. Carat Weight
2 x 1 0.02
2 x 1.5 0.04
2 x 1.75 0.04
2.25 x 1.75 0.04
2.25 x 2 0.045
2.5 x 1 0.045
2.5 x 1.25 0.047
2.5 x 1.5 0.05
2.5 x 1.75 0.055
2.5 x 2 0.055
2.75 x 1.5 0.055
2.75 x 1.75 0.06
2.75 x 2 0.06
2.75 x 2.5 0.065
3 x 1 0.05
3 x 1.25 0.055
3 x 1.5 0.06
3 x 1.75 0.08
3 x 2 0.1
3 x 2.5 0.13
3.25 x 1.25 0.06
3.25 x 1.5 0.065
3.25 x 1.75 0.08
3.25 x 2.5 0.14
3.5 x 1 0.065
3.5 x 1.25 0.07
3.5 x 1.5 0.07
3.5 x 1.75 0.08
3.5 x 2 0.13
3.5 x 2.5 0.15
3.5 x 3 0.15
Dimensions (mm) Approx. Carat Weight
3.75 x 1.5 0.14
3.75 x 2 0.145
4 x 1.25 0.075
4 x 1.5 0.08
4 x 1.75 0.11
4 x 2 0.14
4 x 3 0.2
4.5 x 1.5 0.1
4.5 x 1.75 0.14
4.5 x 2 0.17
4.5 x 2.5 0.2
4.5 x 3 0.285
4.5 x 3.5 0.3
4.75 x 1.5 0.27
4.75 x 2 0.28
5 x 1.5 0.14
5 x 1.75 0.15
5 x 2 0.19
5 x 2.5 0.24
5 x 3 0.3
5 x 3.5 0.33
5 x 4 0.4
5.5 x 1.75 0.16
5.5 x 2 0.18
5.5 x 2.5 0.23
5.5 x 3 0.3
5.5 x 3.5 0.33
6 x 1.75 0.28
6 x 2 0.3
6 x 2.5 0.33
6 x 3 0.4

Shop Baguette Straight Cut

Tapered Baguette Cut

Dimensions (mm) Approx. Carat Weight
2 x 1.5 x 1 0.025
2.5 x 1.5 x 1 0.035
2.5 x 1.75 x 1 0.04
3 x 1.5 x 1 0.05
3 x 1.75 x 1.25 0.055
3 x 1.75 x 1.3 0.055
3 x 1.75 x 1.5 0.055
3 x 2 x 1 0.06
3 x 2 x 1.25 0.065
3 x 2 x 1.5 0.07
3 x 2 x 1.75 0.075
3 x 2.5 x 2 0.08
3.25 x 1.75 x 1 0.07
3.25 x 1.75 x 1.25 0.05
3.5 x 1.25 x 1 0.04
3.5 x 1.5 x 1 0.05
3.5 x 1.5 x 1.25 0.055
3.5 x 1.7 x 1.3 0.055
3.5 x 1.75 x 1 0.06
3.5 x 1.75 x 1.25 0.07
3.5 x 1.75 x 1.3 0.065
3.5 x 2 x 1.25 0.08
3.5 x 2 x 1.5 0.09
3.5 x 2.5 x 2 0.09
3.75 x 2 x 1.25 0.08
4 x 1.5 x 1 0.07
4 x 1.5 x 1.2 0.08
4 x 1.75 x 1.25 0.08
4 x 2 x 1.5 0.1
4 x 2.5 x 1.5 0.12
4 x 2.5 x 2 0.21
4 x 3 x 2 0.21
4.25 x 2 x 1.25 0.11
Dimensions (mm) Approx. Carat Weight
4.25 x 2 x 1.5 0.13
4.25 x 2.5 x 1.25 0.13
4.25 x 2.5 x 1.5 0.135
4.5 x 1.75 x 1.25 0.15
4.5 x 2 x 1.5 0.12
4.5 x 2.3 x 1.8 0.16
4.5 x 2.5 x 2 0.15
4.5 x 2.75 x 1.75 0.15
4.5 x 3 x 2 0.16
4.5 x 3 x 2.5 0.16
4.75 x 2.5 x 1.5 0.15
4.75 x 3 x 2 0.18
5 x 2 x 1 0.14
5 x 2 x 1.25 0.15
5 x 2 x 1.5 0.15
5 x 2.3 x 1.8 0.16
5 x 2.5 x 1.5 0.2
5 x 2.5 x 2 0.21
5 x 2.75 x 2 0.21
5 x 3 x 2 0.25
5 x 3.5 x 2 0.26
5 x 4 x 3.5 0.28
5.5 x 2 x 1.5 0.18
5.5 x 2.5 x 1.75 0.23
5.5 x 2.5 x 2 0.23
5.5 x 3 x 2 0.26
5.5 x 3 x 2.25 0.26
5.5 x 4 x 2.5 0.28
6 x 2 x 1.5 0.3
6 x 2.5 x 1.5 0.3
6 x 3 x 2 0.3
6.5 x 2.5 x 2 0.3
6.5 x 3 x 2 0.32

Shop Tapered Baguette Cut