Diamond’s Measurements: Complete Diamond Size Charts Guide

Diamonds are measured in millimeters and carat weight. Regardless of the gem’s shape, both measurements can be found on the certificate, so look for these numbers when shopping for diamonds.

When it comes to the carats or weight, there’s no point in measuring diamonds that are already embedded in jewelry. What’s most often measured are loose diamonds.

Now, you might be wondering what loose diamonds are. The answer is pretty simple: They’re cut and polished diamonds that are yet to be made into a piece of jewelry.

If you’ve ever wondered why diamonds are so expensive and considered rare, the answer is: It’s because it takes around 250 tons of rock mining to make one single carat diamond. Knowing that, it’s not hard to understand why just 0.5 ct makes a considerable price difference.

Although carat weight is the standard measurement for diamonds, millimeter measurements are just as important. And today, you’re going to learn all about diamond sizing, ratios, charts – and everything in between.

So, without further ado, let’s dive into the nitty-gritty of this diamond size chart guide!

Is Diamond Millimeter Measurement Important?

The millimeter measurement is just as crucial as carat weight because it tells you the diamond’s actual size. You might think that carat and millimeter measurements change proportionally – but that isn’t always the case.

In other words, two diamonds can have the same carat weight, and one can still look larger than the other. That’s because they have different faceting.

Fancy diamond shapes like oval, pear, and emerald look more prominent face up compared to round diamonds.

So, if you think that size matters, you shouldn’t go for the classic round shape.

In non-round diamond shapes, millimeter measurements are a vital factor not just because of the faceting. Great examples here are the cushion and emerald-shaped diamonds.

Measurements expressed in millimeters in cushion diamonds will indicate if they’re squarish, while emerald-shaped diamonds will have rectangular shapes.

If this seems a little confusing, one quick look at the diamond size charts will make everything crystal clear. So, keep reading!

Related Read: Which Diamond Carat Is Best For A Ring?

Already Have A Setting?

Diamond’s millimeter measurement becomes even more critical if you’re purchasing a diamond for an existing earring or ring setting.

It can’t just be any Asscher or marquise diamond, for example. The gem’s size must be carefully selected so that it matches the style and setting.

So, when buying, you’ll definitely need to choose a diamond with precise measurements.

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Pointers And Carats

A term you’ll most definitely hear when shopping for diamonds is “pointers” or “points.” So, what does this mean?

In short – points are fractions of a carat.

When a diamond weighs 0.5 carats, it’s a 50-point diamond. Following that logic, a 100-pointer diamond refers to a 1 carat stone, 150-points means it’s a 1.5 carat stone, and so on.

You’re most likely to hear this trade and wholesaler term when purchasing jewelry – especially engagement rings. That’s because these are smaller accent diamonds and easier to describe when talking in points.

Even though each diamond is one of a kind, it’s recommended to know the average millimeter measurements of different carat weights when shopping for one.

By educating yourself about the standard sizes and measurements, you’ll be far more likely to make the best possible choice within a given budget.

Related Read:

The Ultimate Diamond Size Charts Guide

Now that you’re familiar with the correlations between carat weight and millimeter measurement let’s get into the actual numbers.

Ready?

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!

Learn More: Round Brilliant Cut Diamonds: Everything You Need To Know

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.

Learn More: Princess-Cut Diamonds: Everything You Need To Know

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!

Learn More: Radiant Cut Diamonds: Everything You Need To Know

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.

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