Diamond Size Chart | Complete Edition

Diamond Size Guide

Interactive Millimeter to Carat Conversion

Round Princess Cushion Oval Emerald Pear Marquise Radiant Asscher Heart

Round Brilliant

The most popular cut. Diameter is the primary measure of size.

Quick View (Up to 5.00 ct)

Carat Weight	Diameter (mm)
0.25 ct	4.00 mm
0.50 ct	5.00 mm
0.75 ct	6.00 mm
1.00 ct	6.50 mm
1.50 ct	7.50 mm
2.00 ct	8.00 mm
3.00 ct	9.00 mm
4.00 ct	10.50 mm
5.00 ct	11.50 mm

Complete Data Ledger

MM Size	Carat Weight
3.5 mm	0.18 ct
4.0 mm	0.25 ct
4.5 mm	0.34 ct
5.0 mm	0.50 ct
5.5 mm	0.61 ct
6.0 mm	0.75 ct
6.5 mm	1.00 ct
7.0 mm	1.25 ct
7.5 mm	1.50 ct
8.0 mm	2.00 ct
8.5 mm	2.50 ct
9.0 mm	3.00 ct
10.0 mm	3.50 ct
11.0 mm	4.50 ct
12.0 mm	5.66 ct
13.0 mm	7.88 ct
14.0 mm	9.38 ct
15.0 mm	10.79 ct
16.0 mm	13.27 ct
18.0 mm	15.33 ct

Princess Cut

Square cut with sharp corners. Deep cut means smaller face-up size than round.

Quick View (Up to 5.00 ct)

Carat Weight	Width (mm)
0.25 ct	3.25 mm
0.50 ct	4.50 mm
0.75 ct	5.00 mm
1.00 ct	5.50 mm
1.50 ct	6.50 mm
2.00 ct	7.00 mm
3.00 ct	8.00 mm
4.00 ct	9.00 mm
5.00 ct	9.50 mm

Complete Data Ledger

MM Size	Carat Weight
3.25 mm	0.25 ct
4.0 mm	0.39 ct
4.5 mm	0.50 ct
5.0 mm	0.75 ct
5.5 mm	1.00 ct
6.0 mm	1.25 ct
6.5 mm	1.50 ct
7.0 mm	2.00 ct
7.5 mm	2.50 ct
8.0 mm	3.00 ct
8.5 mm	3.50 ct
9.0 mm	4.00 ct
9.5 mm	5.00 ct
10.0 mm	5.62 ct
11.0 mm	7.44 ct
12.0 mm	9.52 ct
13.0 mm	12.66 ct

Emerald Cut

Rectangular step cut. Long lines and large table.

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Carat Weight	Dimensions (mm)
0.25 ct	4.30 x 3.00 mm
0.50 ct	6.00 x 4.00 mm
0.75 ct	6.50 x 4.50 mm
1.00 ct	7.00 x 5.00 mm
1.50 ct	7.50 x 5.50 mm
2.00 ct	8.50 x 6.50 mm
3.00 ct	9.30 x 7.50 mm
4.00 ct	10.00 x 8.00 mm
5.00 ct	11.00 x 9.00 mm

Complete Data Ledger

MM Size	Carat Weight
3 x 2 mm	0.10 ct
4 x 2 mm	0.15 ct
5 x 3 mm	0.29 ct
6 x 4 mm	0.50 ct
7 x 5 mm	1.00 ct
7.5 x 5.5 mm	1.50 ct
8.5 x 6.5 mm	2.00 ct
9 x 7 mm	2.50 ct
9.3 x 7.5 mm	3.00 ct
9.75 x 7.7 mm	3.50 ct
10 x 8 mm	4.00 ct
10.5 x 8.5 mm	4.50 ct
11 x 9 mm	5.00 ct
12 x 10 mm	6.00 ct
13 x 11 mm	9.13 ct
14 x 12 mm	11.26 ct
16 x 12 mm	14.22 ct

Oval Cut

Elongated round shape. Creates an illusion of greater size.

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Carat Weight	Dimensions (mm)
0.25 ct	5.00 x 3.00 mm
0.50 ct	6.00 x 4.00 mm
1.00 ct	7.70 x 5.70 mm
1.50 ct	8.50 x 6.50 mm
2.00 ct	9.00 x 7.00 mm
3.00 ct	12.00 x 8.00 mm
4.00 ct	12.50 x 8.50 mm
5.00 ct	12.00 x 10.00 mm

Complete Data Ledger

MM Size	Carat Weight
3.6 x 2.7 mm	0.10 ct
5 x 3 mm	0.25 ct
6 x 4 mm	0.50 ct
7 x 5 mm	0.75 ct
7.7 x 5.7 mm	1.00 ct
8.5 x 6.5 mm	1.50 ct
9 x 7 mm	2.00 ct
10 x 8 mm	2.50 ct
12 x 8 mm	3.00 ct
12.5 x 8.5 mm	4.00 ct
12 x 10 mm	5.00 ct
13 x 11 mm	6.05 ct
14 x 12 mm	8.21 ct
16 x 14 mm	11.88 ct
20 x 15 mm	14.96 ct

Marquise Cut

Football shape. Maximizes surface area for carats.

Quick View

Carat Weight	Dimensions (mm)
0.25 ct	6.00 x 3.00 mm
0.50 ct	8.00 x 4.00 mm
1.00 ct	10.00 x 5.00 mm
1.50 ct	12.00 x 6.00 mm
2.00 ct	13.00 x 6.50 mm
3.00 ct	15.00 x 7.00 mm
4.00 ct	16.50 x 8.25 mm
5.00 ct	17.00 x 8.50 mm

Complete Data Ledger

MM Size	Carat Weight
4 x 2 mm	0.10 ct
5 x 3 mm	0.20 ct
6 x 3 mm	0.25 ct
8 x 4 mm	0.50 ct
9 x 4.5 mm	0.75 ct
10 x 5 mm	1.00 ct
12 x 6 mm	1.50 ct
13 x 6.5 mm	2.00 ct
14 x 7 mm	2.50 ct
15 x 7 mm	3.00 ct
16.5 x 8.25 mm	4.00 ct
17 x 8.5 mm	5.00 ct
20 x 11 mm	9.50 ct

Pear Cut

Teardrop shape combining round and marquise.

Quick View

Carat Weight	Dimensions (mm)
0.25 ct	5.00 x 3.00 mm
0.50 ct	6.00 x 4.00 mm
1.00 ct	7.70 x 5.70 mm
1.50 ct	8.50 x 6.50 mm
2.00 ct	9.00 x 7.00 mm
3.00 ct	12.00 x 8.00 mm
4.00 ct	14.00 x 8.00 mm
5.00 ct	15.00 x 9.00 mm

Complete Data Ledger

MM Size	Carat Weight
5 x 3 mm	0.25 ct
6 x 4 mm	0.50 ct
7 x 5 mm	0.75 ct
7.7 x 5.7 mm	1.00 ct
8.5 x 6.5 mm	1.50 ct
9 x 7 mm	2.00 ct
10 x 8 mm	2.50 ct
12 x 8 mm	3.00 ct
14 x 8 mm	4.00 ct
15 x 9 mm	5.00 ct
15 x 10 mm	5.75 ct
18 x 11 mm	8.14 ct
18 x 13 mm	10.21 ct

Radiant Cut

Rectangular like emerald, but with brilliant facets for sparkle.

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Carat Weight	Dimensions (mm)
0.25 ct	4.30 x 3.00 mm
0.50 ct	6.00 x 4.00 mm
1.00 ct	7.00 x 5.00 mm
1.50 ct	7.50 x 5.80 mm
2.00 ct	8.20 x 6.20 mm
3.00 ct	9.50 x 7.50 mm
4.00 ct	10.20 x 8.20 mm
5.00 ct	11.00 x 9.00 mm

Complete Data Ledger

MM Size	Carat Weight
4.3 x 3 mm	0.25 ct
6 x 4 mm	0.50 ct
7 x 5 mm	1.00 ct
7.5 x 5.8 mm	1.50 ct
8.2 x 6.2 mm	2.00 ct
9.5 x 7.5 mm	3.00 ct
10.2 x 8.2 mm	4.00 ct
11 x 9 mm	5.00 ct
13 x 9 mm	6.54 ct
14 x 10 mm	8.47 ct
15 x 11 mm	11.48 ct
16 x 12 mm	14.22 ct

Cushion Cut

Pillow shaped. Soft corners with a high crown.

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Carat Weight	MM Size (Approx)
0.25 ct	3.50 mm
0.50 ct	4.50 mm
1.00 ct	5.50 mm
1.50 ct	6.50 mm
2.00 ct	7.00 mm
3.00 ct	8.00 mm
4.00 ct	9.00 mm
5.00 ct	9.50 mm

Complete Data Ledger

MM Size	Carat Weight
3.25 mm	0.25 ct
4.5 mm	0.50 ct
5.5 mm	1.00 ct
6.5 mm	1.50 ct
7.0 mm	2.00 ct
7.5 mm	2.50 ct
8.0 mm	3.00 ct
8.5 mm	3.50 ct
9.0 mm	4.00 ct
9.5 mm	5.00 ct
11.0 mm	7.44 ct
12.0 mm	9.52 ct
13.0 mm	12.66 ct

Asscher Cut

Square emerald cut. Distinctive X pattern.

Quick View

Carat Weight	MM Size
0.50 ct	4.40 mm
1.00 ct	5.50 mm
1.50 ct	6.30 mm
2.00 ct	7.00 mm
3.00 ct	8.00 mm
4.00 ct	9.00 mm
5.00 ct	9.50 mm

Complete Data Ledger

MM Size	Carat Weight
3.25 mm	0.25 ct
4.5 mm	0.50 ct
5.5 mm	1.00 ct
6.5 mm	1.50 ct
7.0 mm	2.00 ct
8.0 mm	3.00 ct
9.0 mm	4.00 ct
9.5 mm	5.00 ct
11.0 mm	7.44 ct
12.0 mm	9.52 ct
13.0 mm	12.66 ct

Heart Cut

A modified brilliant cut. The symbol of romance.

Quick View

Carat Weight	MM Size (Width)
0.50 ct	5.00 mm
1.00 ct	6.50 mm
1.50 ct	7.30 mm
2.00 ct	8.00 mm
3.00 ct	9.00 mm
4.00 ct	10.00 mm
5.00 ct	11.00 mm

Complete Data Ledger

MM Size	Carat Weight
3.5 mm	0.18 ct
4.5 mm	0.34 ct
5.5 mm	0.61 ct
6.5 mm	1.00 ct
7.5 mm	1.50 ct
8.0 mm	2.00 ct
9.0 mm	3.00 ct
11.0 mm	4.50 ct
12.0 mm	5.66 ct
14.0 mm	9.38 ct