Diamond Carat Weight

Not Reviewed
Calculator / Last modified by KurtHeckman on 2018/03/19 13:45
Round Brilliant Triangular Brilliant
Oval Brilliant Marquise Brilliant
Heart Shaped Pear-shape Brilliant
Emerald Cut Old European
Baguette Tapered Baguette
Princess Cut Cushion

The Diamond Carat Weight Calculator accurately calculates the carat weight of diamonds.  AllCuts2.pngDiamond weights are based on their cut (shapes such as Princess), dimensions and the specific gravity of diamonds.

DIAMOND CARAT (Weight) ESTIMATES:The Diamond Weight formulas contains carat weight equations that are specific to diamonds and diamond cuts including the following:

For the carat weight estimation of other gems (e.g. ruby, sapphire), CLICK HERE.

NOTE: Never use an estimating equation for the weight of a gem if you can weigh it on a quality jeweler's scale.  These equations are useful when the jeweler is trying to preserve the setting of the gem while still providing a carat weight estimate.  In this way, the jeweler can ascertain the type of gem, its shape and then using precise measuring tools measure the salient dimensions for use in these equations.  These steps can be done while the gem remains in the setting.

The vCalc Jeweler's calculator is free to use like all the other equations and calculators found in vCalc.  Please feel free to comment on this wiki page using the comment button below and help us make a better Jeweler calculator for you.AllCuts.png


This calculator provides Jewelers and other merchants of diamonds to compute an estimated current market value for jewelry items.  Likewise private owners and insurance providers can make similar estimates for use in establishing the basis for insurance valuation and coverage.


The equations and data used in vCalc's jewelry library and calculator were reviewed by a certified gemologist.   The equations are based on industry recognized formulas and data.  The table below shows a comparison of computations between vCalc and an industry accepted application (Quantum Leap).

The length, width and depth are in millimeters (mm), and the Quantum Leap and vCalc measurements are in carats (cwt).


The largest variance, an oval faceted alexandrite, which can be seen in the last row above, has been double checked against several source equations which tend to support vCalc's accuracy.

See Also

  • Jeweler's Calculator - Carat weight estimator for diamonds and other gems, and suite of tools for estimating the value of scrap precious metals.
  • Precious Metals Calculator - Near real-time quotes on the SPOT price of Gold, Platinum, Palladium and Silver, with formulas that calculate buy price based on SPOT price, purity (% or karat), refiner's fee and profit (fee).