Diamond Carat to mm Calculator
Convert diamond carat weight to approximate millimeter diameter for round brilliant cut diamonds.
carats
Approximate Diameter
6.50 mm
Weight in Milligrams200 mg
Weight in Grams0.20 g
Approximate Diameter vs Diamond Weight
Diamond Carat to Millimeter Conversion
Diamond size (diameter) relates to carat weight through the cube root, since volume increases with the cube of the diameter.
Formula (Round Brilliant)
Diameter (mm) = 6.5 x Carat^(1/3)
One carat equals 200 milligrams (0.2 grams). A 1-carat round diamond is approximately 6.5 mm in diameter. Doubling the carat weight only increases diameter by about 26% (cube root of 2).
Example Calculation
A 1.0 carat round brilliant diamond.
- 01Diameter = 6.5 x 1.0^(1/3) = 6.5 x 1.0 = 6.5 mm
- 02Weight = 1.0 x 200 = 200 mg
- 03Weight = 1.0 x 0.2 = 0.2 grams
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