Enter the initial moisture content, final moisture content, and the total change in time into the calculator to determine the drying rate.

Drying Rate Formula

The following equation is used to calculate the Drying Rate.

Rc =( Xi - Xf ) / tc
  • Where Rc is the drying rate (%/s)
  • Xi is the initial moisture content (%)
  • Xf is the final moisture content (%)
  • tc is the total time elapsed (s)

To calculate the drying rate, subtract the final moisture content from the initial moisture content, then divide by the time.

In this case, the moisture content is presented as a percentage of dry mass, but units of weight of moisture could be substituted.

What is a Drying Rate?


A drying rate is the rate at which a substance looses it’s moisture content. It’s typically measured as a percentage of moisture per unit time.

How to Calculate Drying Rate?

Example Problem:

The following example outlines the steps and information needed to calculate Drying Rate.

First, determine the initial moisture content. In this example, the initial moisture content is found to be 75%.

Next, determine the final moisture content. In this case, the final moisture content is measured to be 25%.

Next, determine the total time that has passed. For this problem, the total time is 100 seconds.

Finally, calculate the drying rate using the formula above:

Rc =( Xi – Xf ) / tc

Rc =( 75 – 25 ) / 100

Rc = 0.5% / second