Aug 252013

A quick post about calculating diamond depth in a round diamond.

If you have a diamonds measurements, you can calculate the total depth of the diamond.  The total depth is a quick guide to ensure the diamond is ‘OK’.

To calculate the depth you divide the depth by the average of the  the minimum & maximum diameter.  The weight of the diamond does not have any impact.  The formula is the same for a 0.25ct diamond or a 50.00ct diamond.  Lets do a couple:

Measurements: 6.20 – 6.30 x 4.10

Depth / Average Diamater * 100

4.10 / 6.25 * 100 = 65.6% total depth   <- This diamond is quite deep and will not score a very high cut grade.


Measurements: 6.72 x 6.75 x 4.07

4.07 / 6.735 * 100 = 60.4% total depth <- This diamond has the potential to be very attractive.


That’s it!  This is for round diamonds, other shapes use different formulas.