Carat Calculator

The carat weight of a gem can be calculated using the formula:

TCW = Facet Style Factor × Girdle Length × Girdle Width × Depth × Specific Gravity

Selecting a gemstone from the library of gemstones will automatically supply the IGS specific gravity range. Non-IGS values will be marked with a double dagger (‡) before the gemstone name. Just start typing the gem’s name and a list will appear. Select your gem from the list. If your gemstone is not included in the library, you will need to supply the specific gravity values.

Carat Weight Calculator

Calculations are automatic once all required values are supplied or changed.