The marquise cut and the pear cut are somewhat similar in terms of shape: Both have an oval-looking outline, but the marquise cut has two pointed ends, whereas the pear cut has only one. If you have a diamond with either of these shapes but don’t know its carat weight, you can estimate it by using one of the conversion tables below.
Keep in mind that an estimate of a diamond’s weight will be far from precise, but it will at least indicate the approximate carat your stone is likely to have.
Millimeter-to-Carat Conversion Table for Marquise-Cut Diamonds
To estimate the carat weight of your marquise diamond, measure its length and width, and then find below the length-width pair that is closest to your measurement – the corresponding carat weight on the right is the approximate guess for the actual weight of your diamond:
4.0 x 2.0 mm – 0.10 ct
5.0 x 2.0 mm – 0.20 ct
6.5 x 3.0 mm – 0.25 ct
8.5 x 4.0 mm – 0.50 ct
9.5 x 4.5 mm – 0.75 ct
10.0 x 5.0 mm – 1.00 ct
11.0 x 5.5 mm – 1.25 ct
12.0 x 6.0 mm – 1.50 ct
13.0 x 6.5 mm – 2.00 ct
14.0 x 7.0 mm – 3.00 ct
16.0 x 8.0 mm – 4.00 ct
17.0 x 9.0 mm – 5.00 ct
Millimeter-to-Carat Conversion Table for Pear-Cut Diamonds
Measure the length and width of your pear-cut diamond, and look at the left column in the table below to find the value that is closest to the measurements you’ve taken.
The carat number on the right is the estimate of how much your diamond should weight approximately:
4.0 x 2.0 mm – 0.20 ct
5.5 x 3.5 mm – 0.25 ct
7.0 x 4.5 mm – 0.50 ct
8.0 x 5.0 mm – 0.75 ct
8.5 x 5.5 mm – 1.00 ct
9.5 x 6.0 mm – 1.25 ct
10.0 x 6.5 mm – 1.50 ct
10.5 x 7.0 mm – 2.00 ct
11.0 x 7.0 mm – 2.50 ct
12.5 x 8.0 mm – 3.00 ct
13.0 x 8.5 mm – 3.50 ct
14.0 x 9.0 mm – 4.00 ct
15.0 x 9.5 mm – 5.00 ct
Note: Keep in mind that these tables will give you a number for your stone’s weight that is imprecise. Consider adding a margin of error of about +/- 10-20% of the estimated carat weight to get an idea of the range in which the actual weight of your diamond is likely to fall.
Where to Buy Diamond Jewelry?
We recommend James Allen (read review) because you can see a 360-degree video for any diamond before buying it.
Blue Nile is another reputable diamond retailer we recommend.
