Enter the assay on the as-is basis and the water percentage into the calculator to determine the anhydrous basis.

Anhydrous Basis Formula

The following equation is used to calculate the Anhydrous Basis.

AB = (AOB*100)/(100-PW)
  • Where Ab is the Anhydrous Basis
  • AOB is the assay on as-is basis
  • W is the percentage of water (%)

How to Calculate Anhydrous Basis?

Example Problem:

The following example outlines the steps and information needed to calculate Anhydrous Basis.

First, determine the assay on as-is basis. In this case, this value is found to be .56.

Next, determine the water percentage. This is measured to be 50%.

Finally, calculate the Anhydrous Basis using the formula above:

AB = (AOB*100)/(100-%W)

AB = (.56*100)/(100-50)

AB = 1.12