Want to see how a round cut diamond looks on your hand at 1, 2, or more carats? You’re in the right place. We made the chart and images below to give you an idea of how big round cut diamonds are at different weights.

Round Diamond Dimensions & Sizes

Height	Width	Round Weight (ct)
0.8 mm.	0.8 mm.	0.0025 ct.
1 mm.	1 mm.	0.005 ct.
1.1 mm.	1.1 mm.	0.0067 ct.
1.2 mm.	1.2 mm.	0.009 ct.
1.25 mm.	1.25 mm.	0.01 ct.
1.3 mm.	1.3 mm.	0.01 ct.
1.5 mm.	1.5 mm.	0.015 ct.
1.75 mm.	1.75 mm.	0.02 ct.
1.8 mm.	1.8 mm.	0.025 ct.
2 mm.	2 mm.	0.03 ct.
2.2 mm.	2.2 mm.	0.04 ct.
2.5 mm.	2.5 mm.	0.06 ct.
2.75 mm.	2.75 mm.	0.08 ct.
3 mm.	3 mm.	0.10 ct.
3.25 mm.	3.25 mm.	0.14 ct.
3.5 mm.	3.5 mm.	0.17 ct.
3.75 mm.	3.75 mm.	0.21 ct.
4 mm.	4 mm.	0.25 ct.
4.25 mm.	4.25 mm.	0.28 ct.
4.5 mm.	4.5 mm.	0.36 ct.
4.75 mm.	4.75 mm.	0.44 ct.
5.0 mm.	5.0 mm.	0.50 ct.
5.25 mm.	5.25 mm.	0.56 ct.
5.5 mm.	5.5 mm.	0.66 ct.
5.75 mm.	5.75 mm.	0.75 ct.
6 mm.	6 mm.	0.84 ct.
6.25 mm.	6.25 mm.	0.93 ct.
6.5 mm.	6.5 mm.	1.00 ct.
6.8 mm.	6.8 mm.	1.25 ct.
7 mm.	7 mm.	1.30 ct.
7.3 mm.	7.3 mm.	1.50 ct.
7.5 mm.	7.5 mm.	1.67 ct.
7.75 mm.	7.75 mm.	1.75 ct.
8 mm.	8 mm.	2.00 ct.
8.25 mm.	8.25 mm.	2.11 ct.
8.5 mm.	8.5 mm.	2.43 ct.
8.7 mm.	8.7 mm.	2.50 ct.
9 mm.	9 mm.	2.75 ct.
9.1 mm.	9.1 mm.	3.00 ct.
9.5 mm.	9.5 mm.	3.35 ct.
9.75 mm.	9.75 mm.	3.61 ct.
10 mm.	10 mm.	3.87 ct.
10.25 mm.	10.25 mm.	4.16 ct.
10.5 mm.	10.5 mm.	4.41 ct.
10.75 mm.	10.75 mm.	4.57 ct.
11 mm.	11 mm.	4.91 ct.
11.25 mm.	11.25 mm.	5.49 ct.
11.5 mm.	11.5 mm.	5.85 ct.
12 mm.	12 mm.	6.84 ct.
12.25 mm.	12.25 mm.	7.26 ct.
12.5 mm.	12.5 mm.	7.36 ct.
12.75 mm.	12.75 mm.	7.52 ct.
13 mm.	13 mm.	8.51 ct.
13.5 mm.	13.5 mm.	9.53 ct.
14 mm.	14 mm.	10.49 ct.
15 mm.	15 mm.	12.89 ct.
16 mm.	16 mm.	16.06 ct.

What are a Round Cut Diamond’s Dimensions?

A round cut diamond has a round, symmetrical shape with 57 or 58 facets. It’s also known as a round cut, round brilliant cut, and round shaped diamond. A round cut diamond with good symmetry will have a length-to-width ratio of 1.00 - 1.02.

About the Round Cut Diamond

Round cut diamonds

Round shaped diamonds go way back, but they were mostly crooked in their early days. In fact, symmetrical rounds were not even possible until the late 1800s. This was when the bruting machine was invented to cut diamonds into a round shape.

In 1919, Marcel Tolkowsky dropped another bombshell. He published Diamond Design: A Study of the Reflection and Refraction of Light in Diamond. His mathematical formula introduced proportion in cutting round diamonds. The formula went through many stages of refinement over the years.

Today, the round is one of the most sought-after cuts for engagement rings and other jewelry. It represents over two-thirds of all diamonds sold. The reason? Unrivaled brilliance and fire.

Learn about Round Cut Diamonds

Maximising Your Round Cut Diamond’s Size

Round diamonds are the only ones that the GIA grades for cut: the most important of the 4 C’s. Rounds don't show color as much as other cuts. So it's possible to go quite low on the color scale without noticing much difference. J and higher grades work well for white gold and platinum settings. You can drop to K for yellow and rose gold settings.

Clarity is another area you can spend a little less on. Rounds are great at masking inclusions. As long as the diamond is eye-clean, an SI1 or SI2 clarity will offer great value for money.

FAQ

1. Is a 1 carat diamond big enough?

This may seem small to some but a 1-carat diamond is definitely big enough to draw attention. Size and carat weight should be a consideration for your ring, but pay attention also to the cut.

2. What is the most popular carat size for engagement rings?

It’s typically around one carat but the size differs from one part of the world to the other. In the United States, for example, the average for an engagement ring is around one carat. In Europe, it's around 0.6 - 0.5 carats.

3. How big is a round cut diamond compared to others?

Many square shaped diamonds such as princess and cushion have higher depth. This makes them appear smaller than comparable rounds. Check out the table below, comparing a few other cuts with rounds:

Shape	Carat Weight	Millimeter Size
Round	1.00ct	6.5mm
Square Cushion	1.00ct	5.9mm
Princess	1.00ct	5.5mm
Asscher	1.00ct	5.5mm

Round Cut Diamond Size (Chart, Dimensions, On Hand)

You might also like to read

Princess Cut Diamond Size (Chart, Dimensions, On Hand)

Pear Cut Diamond Size (Chart, Dimensions, On Hand)

Radiant Cut Diamond Size (Chart, Dimensions, On Hand)