MM to Carat Weight Conversion Values · Thomas Laine Jewelry · Explore design-led engagement rings, fine jewelry, and bespoke pieces — all crafted with intention and backed by 20+ years of diamond expertise.

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Select a shape to view it's respective chart.

Round cut millimeters (mm) to carat weight conversion chart:

MM Size	Carat weight
0.8	0.0025
1	0.005
1.10	0.0075
1.15	0.0067
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
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

Princess cut millimeters (mm) to carat weight conversion chart:

MM Size	Carat weight
1.5	0.015
1.75	0.03
2	0.06
2.25	0.08
2.5	0.1
2.75	0.13
3	0.18
3.25	0.26
3.5	0.29
3.75	0.31
4	0.39
4.25	0.44
4.5	0.56
4.75	0.64
5	0.71
5.25	0.75
5.5	0.99
5.75	1.11
6	1.24
6.25	1.39
6.5	1.59
6.75	1.75
7	1.96
7.25	2.01
7.5	2.4
7.75	2.74
8	3.01
8.25	3.24
8.5	3.67
8.75	4.1
9	4.12
9.5	5.09
9.75	5.36
10	5.62
10.25	5.76
10.5	5.99
11	7.44
11.5	9.44
12	9.52

Asscher cut millimeters (mm) to carat weight conversion chart:

MM Size	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
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

Heart cut millimeters (mm) to carat weight conversion chart:

MM Size	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
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

Cushion cut millimeters (mm) to carat weight conversion chart:

MM Size	Carat weight
4	0.25
4.5	0.36
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
7	1.28
7.5	1.67
8	2.04
8.5	2.43
9	2.75
9.5	3.35
10	3.87
10.5	4.41
11	4.91
11.5	5.85
12	6.84
13	8.51
14	10.49
15	12.89