Diamond Carat

A diamond's weight is measured in carats. One carat is equal to 0.2 grams. The larger the carat the heavier the diamond.

One Diamond carat is divided into 100 point. A 0.25 carat diamond is the same as a 25 points or 1/4 carat diamond. Carat is often confused with size even though it is actually a measure of weight.

Top Tips

To help you choose the perfect diamond carat, we have collated a few top tips

finger Size

When choosing a diamond for a ring, it is also important to consider the length and width of the ring finger. A diamond will appear larger on longer and slimmer fingers and by comparison, shorter and wider fingers tend to make diamonds appear smaller.

Setting Style

When deciding on a diamond for a particular jewelry setting, the appearance in size and weight can be altered depending on the type and proportions of the setting. Delicate and slender settings tend to enhance the size and prominence of a diamond centerpiece, while larger and more solid settings can make the diamond appear smaller.

Pricing Help

If you are on a tight budget, don't worry. Look for diamonds that fall just under popular carat weights such as 0.40, 0.90 or 1.75. These diamonds fall just shy of the most popular diamond carats, and they are often sold at a more preferable rate than full-carat diamonds. For example, a 0.90 carat diamond will typically cost less on a price-per-carat basis than a 1.00 carat diamond. Visually it's difficult to distinguish the difference between a 0.90 carat diamond and a 1.00 carat diamond.

Shapes can make diamonds look larger

Some shapes can make a smaller carat diamond look larger. For example, if a diamond of 0.30 carat is required to fit your budget, consider a marquise diamond cut as this appears larger than other shapes of equal carat, due to its elongated cut.

Diamond Carat Size Chart

MM SIZE	CT WEIGHT
0.8 mm.	0.0025 ct.
1 mm.	0.005 ct.
1.12 mm.	0.0067 ct.
1.15 mm.	0.0075 ct.
1.25 mm.	0.01 ct.
1.3 mm.	0.01 ct.
1.5 mm.	0.015 ct.
1.75 mm.	0.02 ct.
1.8 mm.	0.025 ct.
2 mm.	0.03 ct.
2.25 mm.	0.04 ct.
2.5 mm.	0.06 ct.
2.75 mm.	0.08 ct.
3 mm.	0.11 ct.
3.25 mm.	0.14 ct.
3.5 mm.	0.17 ct.
3.75 mm.	0.21 ct.
4 mm.	0.25 ct.
4.25 mm.	0.28 ct.

MM SIZE	CT WEIGHT
4.5 mm.	0.36 ct.
4.75 mm.	0.44 ct.
5.0 mm.	0.50 ct.
5.25 mm.	0.56 ct.
5.5 mm.	0.66 ct.
5.75 mm.	0.75 ct.
6.25 mm.	0.93 ct.
6.5 mm.	1.00 ct.
6.8 mm.	1.25 ct.
7 mm.	1.30 ct.
7.3 mm.	1.50 ct.
7.5 mm.	1.67 ct.
7.75 mm.	1.75 ct.
8 mm.	2.00 ct.
8.25 mm.	2.11 ct.
8.5 mm.	2.43 ct.
8.7 mm.	2.50 ct.
9 mm.	2.75 ct.
9.1 mm.	3.00 ct.

MM SIZE	CT WEIGHT
9.5 mm.	3.35 ct.
9.75 mm.	3.61 ct.
10 mm.	3.87 ct.
10.25 mm.	4.16 ct.
10.5 mm.	4.41 ct.
10.75 mm.	4.57 ct.
11 mm.	4.91 ct.
11.25 mm.	5.49 ct.
11.5 mm.	5.85 ct.
12 mm.	6.84 ct.
12.25 mm.	7.26 ct.
12.5 mm.	7.36 ct.
12.75 mm.	7.52 ct.
13 mm.	8.51 ct.
13.5 mm.	9.53 ct.
14 mm.	10.49 ct.
15 mm.	12.89 ct.
16 mm.	16.06 ct.

Notes

Carat is measurement of WEIGHT, not SIZE and the overall diameter (mm) could differe slighter larger or smaller even through carat weight is correct.
Image not to scale. Diamond pictures are shown for comparison purpose only. Actual size can very depending your screen resolutions, monitor size etc.

MM SIZE	CT WEIGHT
1.5 mm.	0.015 ct.
1.75 mm.	0.03 ct.
2 mm.	0.06 ct.
2.25 mm.	0.08 ct.
2.5 mm.	0.10 ct.
2.75 mm.	0.13 ct.
3 mm.	0.18 ct.
3.25 mm.	0.26 ct.
3.5 mm.	0.29 ct.
3.75 mm.	0.31 ct.
4 mm.	0.39 ct.
4.25 mm.	0.44 ct.
4.5 mm.	0.50 ct.

MM SIZE	CT WEIGHT
4.75 mm.	0.64 ct.
5 mm.	0.75 ct.
5.25 mm.	0.90 ct.
5.5 mm.	1.00 ct.
5.75 mm.	1.11 ct.
6 mm.	1.25 ct.
6.25 mm.	1.39 ct.
6.5 mm.	1.50 ct.
6.75 mm.	1.75 ct.
7 mm.	2.00 ct.
7.25 mm.	2.01 ct.
7.5 mm.	2.50 ct.
7.75 mm.	2.74 ct.

MM SIZE	CT WEIGHT
8 mm.	3.00 ct.
8.25 mm.	3.24 ct.
8.5 mm.	3.67 ct.
8.75 mm.	4.10 ct.
9 mm.	4.12 ct.
9.5 mm.	5.09 ct.
9.75 mm.	5.36 ct.
10 mm.	5.62 ct.
10.25 mm.	5.76 ct.
10.5 mm.	5.99 ct.
11 mm.	7.44 ct.
11.5 mm.	9.44 ct.
12 mm.	9.52 ct.

Notes

Carat is measurement of WEIGHT, not SIZE and the overall diameter (mm) could differe slighter larger or smaller even through carat weight is correct.
Image not to scale. Diamond pictures are shown for comparison purpose only. Actual size can very depending your screen resolutions, monitor size etc.

MM SIZE	CT WEIGHT
3x1.5 mm.	0.025 ct.
3.5x1.75 mm.	0.065 ct.
3.5x2 mm.	0.07 ct.
4x2 mm.	0.10 ct.
3.75x1.75 mm.	0.11 ct.
4.25x2.25 mm.	0.12 ct.
5x2.5 mm.	0.14 ct.
5.5x2.75 mm.	0.16 ct.
5.5x3 mm.	0.18 ct.
5x3 mm.	0.20 ct.
6.5x3 mm.	0.23 ct.
6x3 mm.	0.25 ct.

MM SIZE	CT WEIGHT
7x3 mm.	0.30 ct.
7.5x3.5 mm.	0.33 ct.
7x4 mm.	0.34 ct.
8x4 mm.	0.50 ct.
8.75x4.25 mm.	0.70 ct.
9x4.5 mm.	0.75 ct.
9.5x4.7 mm.	0.85 ct.
10x5 mm.	1.00 ct.
11x5.5 mm.	1.25 ct.
11.5x6 mm.	1.33 ct.
12x6 mm.	1.50 ct.
13x6.5 mm.	2.00 ct.

MM SIZE	CT WEIGHT
14x7 mm.	2.50 ct.
15x7 mm.	3.00 ct.
14x8 mm.	3.00 ct.
15x7.5 mm.	3.25 ct.
15x8 mm.	3.44 ct.
16x8 mm.	3.86 ct.
16.5x8.25 mm.	4.00 ct.
17x8.5 mm.	4.88 ct.
17.5x10 mm.	5.50 ct.
20x8 mm.	7.08 ct.
20x10 mm.	7.94 ct.
20x11 mm.	9.50 ct.