Diamond calculator question?

[honeyxxxbear]

We were playing with the DiamCalc program, to see how proportions changed cut.
My question is, we entered the proportions for my stone and the carat weight would read .84, (my stone is a .82) how accurate is the program? If we change to correct weight the proportions would also change.
Also for a marquise cut, to figure out weight do we;
LxWxDx.0058=ct. Would this be accurate?
Thank you

 

[Garry H (Cut Nut)]

The calculations are deadly accurate, but there are many variables - for instance your diamond may have a different pattern of facets, and it probably has a slightly different shape to the design used on DiamCalc.
The weight estimation formulas for all shapes of diamonds are approximations and can not allow for girdle thickness - the biggest variable of all. Would you like me to ask Sergey to respond or is this an adequate response?