Enter the total amount of rainfall (in) and the total amount of evaporation (in) into the Effective Rainfall Calculator. The calculator will evaluate the Effective Rainfall. 

Effective Rainfall Formula

The following two example problems outline the steps and information needed to calculate the Effective Rainfall.

ER = RF - E

Variables:

  • ER is the Effective Rainfall (in)
  • RF is the total amount of rainfall (in) 
  • E is the total amount of evaporation (in) 

To calculate the effective rainfall, subtract the evaporation amount from the total rainfall.

How to Calculate Effective Rainfall?

The following steps outline how to calculate the Effective Rainfall.


  1. First, determine the total amount of rainfall (in). 
  2. Next, determine the total amount of evaporation (in). 
  3. Next, gather the formula from above = ER = RF - E.
  4. Finally, calculate the Effective Rainfall.
  5. After inserting the variables and calculating the result, check your answer with the calculator above.

Example Problem : 

Use the following variables as an example problem to test your knowledge.

total amount of rainfall (in) = 1.25

total amount of evaporation (in) = .30

ER = RF - E = ?