Full Diamond Size Charts Guide

Diamonds are typically measured in millimeters and carat weight, and both of these measurements can be found on the diamond certificate. When shopping for diamonds, it’s important to look for these numbers.

Carat weight is particularly relevant for loose diamonds rather than those already set in jewelry. Loose diamonds are diamonds that have been cut and polished but have not yet been incorporated into a piece of jewelry.

The reason diamonds are considered expensive and rare is because it takes approximately 250 tons of mined rock to produce a single carat of diamond. Understanding this, even a slight difference of 0.5 carats can significantly impact the price of a diamond.

While carat weight is the standard measurement for diamonds, the millimeter measurements are equally important. In this guide, you will learn about diamond sizing, ratios, charts, and everything in between.

So, without any further delay, let’s delve into the detailed aspects of this diamond size chart guide!

Is Diamond Millimeter Measurement Important?

The millimeter measurement of a diamond is just as important as its carat weight because it provides information about the actual size of the diamond. It’s worth noting that carat and millimeter measurements do not always change proportionally. This means that two diamonds with the same carat weight can appear different in size due to variations in their faceting.

Fancy diamond shapes such as oval, pear, and emerald tend to look larger when viewed from the top compared to round diamonds. So, if size is a priority for you, opting for a non-round shape might be a better choice.

In non-round diamond shapes, millimeter measurements play a crucial role, not only because of the faceting but also because they help determine specific shape characteristics. For example, cushion-shaped diamonds can vary in their squarish appearance, while emerald-shaped diamonds typically have a rectangular shape.

If you find this information a bit confusing, referring to diamond size charts can provide clarity. These charts offer visual representations of how different carat weights and millimeter measurements correspond to diamond sizes.

Furthermore, when purchasing a diamond for an existing earring or ring setting, the millimeter measurement becomes even more crucial. It’s essential to select a diamond with precise measurements that align with the style and dimensions of the setting.

So, when buying a diamond, be sure to consider both carat weight and millimeter measurements to make an informed decision.

Pointers And Carats 

When you’re shopping for diamonds, you might come across the terms “pointers” or “points.” So, what exactly do these terms mean?

In simple terms, points refer to fractions of a carat. For instance, when a diamond weighs 0.5 carats, it’s referred to as a 50-point diamond. Following this logic, a 100-pointer diamond signifies a 1-carat stone, 150 points indicates a 1.5-carat stone, and so on.

The use of points is commonly heard in the diamond trade and among wholesalers, particularly when discussing jewelry items like engagement rings. This is because smaller accent diamonds are often described in points, making it easier to communicate their sizes.

While each diamond is unique, it’s still helpful to be familiar with the average millimeter measurements associated with different carat weights when you’re in the market for a diamond. By educating yourself about standard sizes and measurements, you’ll be better equipped to make an informed decision within your desired budget.

The Ultimate Diamond Size Charts Guide

Round Diamond Size Chart 

Did you know that round diamonds are the most popular shape? Up to 64% of young adults will choose a round diamond as the centerpiece of their engagement ring!

Size (In Millimeters)	Carat Weight
0.80 mm	0.0025 ct.
1.00 mm	0.0050 ct.
1.12 mm	0.0067 ct.
1.15 mm	0.0075 ct.
1.25 mm	0.010 ct.
1.50 mm	0.015 ct.
1.75 mm	0.020 ct.
1.80 mm	0.025 ct.
2.00 mm	0.030 ct.
2.25 mm	0.040 ct.
2.50 mm	0.060 ct.
2.75 mm	0.080 ct.
3.00 mm	0.11 ct.
3.25 mm	0.14 ct.
3.50 mm	0.17 ct.
3.75 mm	0.21 ct.
4.00 mm	0.25 ct.
4.25 mm	0.28 ct.
4.50 mm	0.36 ct.
4.75 mm	0.44 ct.
5.00 mm	0.5 ct.
5.25 mm	0.56 ct.
5.50 mm	0.66 ct.
5.75 mm	0.75 ct.
6.00 mm	0.84 ct.
6.25 mm	0.93 ct.
6.50 mm	1.00 ct.
6.80 mm	1.25 ct.
7.00 mm	1.30 ct.
7.30 mm	1.50 ct.
7.50 mm	1.67 ct.
7.75 mm	1.75 ct.
8.00 mm	2.00 ct.
8.25 mm	2.11 ct.
8.50 mm	2.43 ct.
8.70 mm	2.50 ct.
9.00 mm	2.75 ct.
9.10 mm	3.00 ct.
9.50 mm	3.35 ct.
9.75 mm	3.61 ct.
10.00 mm	3.87 ct.
10.25 mm	4.16 ct.
10.50 mm	4.41 ct.
10.75 mm	4.57 ct.
11.00 mm	4.91 ct.
11.25 mm	5.49 ct.
11.50 mm	5.85 ct.
12.00 mm	6.84 ct.
12.25 mm	7.26 ct.
12.50 mm	7.36 ct.
12.75 mm	7.52 ct.
13.00 mm	8.51 ct.
13.50 mm	9.53 ct.
14.00 mm	10.49 ct.
15.00 mm	12.89 ct.
16.00 mm	16.06 ct.
17.00 mm	18.00 ct.

Princess Diamond Size Chart

This contemporary diamond cut boasts a geometric, sharp pyramidal shape – characterized by strong lines and four beveled sides. This cut has been around since the 1980s and is known for the astonishing amount of fire it offers. 

Size (In Millimeters)	Carat Weight
1.50 mm	0.015 ct.
1.75 mm	0.03 ct.
2.00 mm	0.06 ct.
2.25 mm	0.08 ct.
2.50 mm	0.10 ct.
2.75 mm	0.13 ct.
3.00 mm	0.18 ct.
3.25 mm	0.26 ct.
3.50 mm	0.29 ct.
3.75 mm	0.31 ct.
4.00 mm	0.39 ct.
4.25 mm	0.44 ct.
4.50 mm	0.50 ct.
4.75 mm	0.64 ct.
5.00 mm	0.75 ct.
5.25 mm	0.75 ct.
5.50 mm	1.00 ct.
5.75 mm	1.11 ct.
6.00 mm	1.25 ct.
6.25 mm	1.39 ct.
6.50 mm	1.50 ct.
6.75 mm	1.75 ct.
7.00 mm	2.00 ct.

Cushion Diamond Size Chart

Cushion-cut diamonds feature a square shape and larger, brilliant-cut facets – but with rounded corners. They resemble a pillow – hence the name. 

Size (In Millimeters)	Carat Weight
4.2 mm	0.40 ct.
4.9 mm	0.50 ct.
5.25 mm	0.75 ct.
5.5 mm	1.00 ct.
6 mm	1.25 ct.
6.5 mm	1.50 ct.
7 mm	2.00 ct.
7.5 mm	2.50 ct.
8 mm	3.00 ct.
8.5 mm	3.50 ct.
9 mm	4.12 ct.
9.5 mm	5.09 ct.
10 mm	5.62 ct.
11 mm	7.44 ct.
12 mm	9.52 ct.
13 mm	12.66 ct.

Emerald Diamond Size Chart

Emerald cut diamonds are among the oldest cuts out there, dating back to the 1500s. They’re known for their elongated, rectangular shape, step cuts, and linear facets. 

Size (In Millimeters)	Carat Weight
3×2 mm	0.10 ct.
3.5×2 mm	0.12 ct.
4×2 mm	0.15 ct.
4×3 mm	0.20 ct.
5×3 mm	0.29 ct.
5.5×3.5 mm	0.46 ct.
6×4 mm	0.50 ct.
6.5×4.5 mm	0.75 ct.
6.5×4.5 mm	0.88 ct.
7×5 mm	1.00 ct.
7.3×5.3 mm	1.25 ct.
7.5×5.5 mm	1.50 ct.
8×6 mm	1.75 ct.
8.5×6.5 mm	2.00 ct.
9×7 mm	2.50 ct.
10×7.5 mm	3.00 ct.
9.5×7.5 mm	3.21 ct.
10×8 mm	3.79 ct.
11×9 mm	5.21 ct.
12×8 mm	5.34 ct.
12×10 mm	6.00 ct.
14×8 mm	6.25 ct.
13×9 mm	6.38 ct.
14×10 mm	8.48 ct.
13×11 mm	9.13 ct.
14×12 mm	11.26 ct.
16×12 mm	14.22 ct.
17×13 mm	16.50 ct.

Related Read: Emerald Cut Vs. Radiant Cut

Oval Diamond Size Chart

If you want the brilliance of a round diamond but in a more unique-looking package, an oval cut diamond is something you should consider! 

Size (In Millimeters)	Carat Weight
4.5×3.5 mm	0.21 ct.
5×3 mm	0.21 ct.
5.5×3.5 mm	0.33 ct.
5×4 mm	0.35 ct.
6×4 mm	0.50 ct.
6×5 mm	0.61 ct.
6.5×4.5 mm	0.65 ct.
7×5 mm	0.75 ct.
7.7×5.7 mm	1.00 ct.
8×6 mm	1.25 ct.
9×6 mm	1.41 ct.
8.5×6.5 mm	1.50 ct.
9×7 mm	2.00 ct.
10×8 mm	2.50 ct.
10.5×8.5 mm	2.88 ct.
12×8 mm	3.00 ct.
11×9 mm	3.85 ct.
12×10 mm	5.05 ct.
14×10 mm	5.81 ct.
13×11 mm	6.05 ct.
14×12 mm	8.21 ct.
15×12 mm	8.76 ct.
16×12 mm	9.32 ct.
16×14 mm	11.88 ct.
18×13 mm	12.86 ct.
20×15 mm	14.96 ct.

Pear Diamond Size Chart

A hybrid of a round and a marquise – but with a tapered point on one side – a pear diamond has the exceptional ability to hide any imperfections inside the gem. It looks larger than a round-cut diamond, too.

Size (In Millimeters)	Carat Weight	Size (In Millimeters)	Carat Weight
3×2 mm	0.13 ct.	12×8 mm	3.00 ct.
4×2.5 mm	0.18 ct.	12×7 mm	3.12 ct.
4×3 mm	0.21 ct.	12×9 mm	3.44 ct.
5×3 mm	0.25 ct.	14×8 mm	3.47 ct.
5×4 mm	0.35 ct.	13×9 mm	4.11 ct.
6×4 mm	0.50 ct.	14×9 mm	4.25 ct.
6.5×4.5 mm	0.60 ct.	15×9 mm	5.06 ct.
7×5 mm	0.75 ct.	14×10 mm	5.41 ct.
7.5×5.5 mm	0.85 ct.	13×11 mm	5.65 ct.
7.7×5.7 mm	1.00 ct.	15×10 mm	5.75 ct.
8×6 mm	1.25 ct.	16×9 mm	5.86 ct.
8.5×6.5 mm	1.50 ct.	16×10 mm	6.27 ct.
10×6 mm	1.71 ct.	17×10 mm	6.46 ct.
8.7×6.7 mm	1.80 ct.	15×11 mm	7.36 ct.
9×7 mm	2.00 ct.	18×11 mm	8.14 ct.
10×8 mm	2.50 ct.	16×12 mm	8.99 ct.
11×7.50 mm	2.61 ct.	18×12 mm	9.35 ct.
13×8 mm	2.98 ct.	18×13 mm	10.21 ct.
11×8 mm	3.00 ct.	19×14 mm	11.70 ct.

Marquise Diamond Size Chart

This diamond cut is characterized by its elongated shape with pointed ends and 58 facets that create the illusion of a larger size.  

Size (In Millimeters)	Carat Weight	Size (In Millimeters)	Carat Weight
3×1.5 mm	0.025 ct.	9.5×2 mm	0.85 ct.
3.5×1.75 mm	0.065 ct.	10×5 mm	1.00 ct.
3.5×2 mm	0.07 ct.	11×5.5 mm	1.25 ct.
4×2 mm	0.10 ct.	11.5×6 mm	1.33 ct.
3.75×1.75 mm	0.11 ct.	12×6 mm	1.50 ct.
4.25×2.25 mm	0.12 ct.	13×6.5 mm	2.00 ct.
5×2.5 mm	0.14 ct.	14×7 mm	2.50 ct.
5.5×2.75 mm	0.16 ct.	15×7 mm	3.00 ct.
5.5×3 mm	0.18 ct.	14×8 mm	3.00 ct.
5×3 mm	0.20 ct.	15×7.5 mm	3.25 ct.
6.5×3 mm	0.23 ct.	15×8 mm	3.44 ct.
6×3 mm	0.25 ct.	16×8 mm	3.86 ct.
7×3 mm	0.30 ct.	16.5×8.25 mm	4.00 ct.
7.5×3.5 mm	0.33 ct.	17×8.5 mm	4.88 ct.
7×4 mm	0.34 ct.	17.5×10 mm	5.50 ct.
8×4 mm	0.50 ct.	20×8 mm	7.08 ct.
8.75×4.25 mm	0.70 ct.	20×10 mm	7.94 ct.
9×4.5 mm	0.75 ct.	20×11 mm	9.50 ct.

Asscher Diamond Size Chart

The Asscher cut – which was invented in 1902 – is an excellent alternative to the emerald cut. Its 58 facets promise more sparkle, too!

Size (In Millimeters)	Carat Weight
4 mm	0.39 ct.
4.5 mm	0.50 ct.
5 mm	0.75 ct.
5.5 mm	1.00 ct.
6 mm	1.25 ct.
6.5 mm	1.50 ct.
7 mm	2.00 ct.
7.5 mm	2.50 ct.
8 mm	3.00 ct.
8.5 mm	3.50 ct.
9 mm	4.12 ct.
9.5 mm	5.09 ct.
10 mm	5.62 ct.
11 mm	7.44 ct.
12 mm	9.52 ct.
13 mm	12.66 ct.

Radiant Diamond Size Chart

This modern shape was invented in 1977 – and is characterized by its vibrant and breathtaking sparkle. It combines the benefits of brilliant cuts (like the round) and step cuts (like the emerald) into one!

Size (In Millimeters)	Carat Weight
5×3 mm	0.31 ct.
4.5×3.5 mm	0.34 ct.
6×3 mm	0.41 ct.
6×4 mm	0.50 ct.
6.5×4.5 mm	0.75 ct.
7×5 mm	1.00 ct.
7.3×5.5 mm	1.25 ct.
7.5×5.8 mm	1.50 ct.
8×6 mm	2.00 ct.
8.5×6.5 mm	2.25 ct.
9×7 mm	2.50 ct.
9.5×7.5 mm	3.00 ct.
10×7 mm	3.31 ct.
10×8 mm	3.50 ct.
11×9 mm	5.05 ct.
12×9 mm	6.06 ct.
11.5×10 mm	6.45 ct.
13×9 mm	6.54 ct.
12×10 mm	6.79 ct.
14×10 mm	8.47 ct.
13×11 mm	9.33 ct.
13.5×11.5 mm	10.19 ct.
15×11 mm	11.48 ct.
14×12 mm	12.14 ct.
16×12 mm	14.22 ct.
17×13 mm	16.22 ct.