Enter the reference evapotranspiration (mm/day) and the crop factor into the Calculator. The calculator will evaluate the Crop Water Use. 

Crop Water Use Formula

Etc = Eto * Kc


  • Etc is the Crop Water Use (mm/day)
  • Eto is the reference evapotranspiration (mm/day)
  • Kc is the crop factor

To calculate Crop Water Use, multiply the reference evapotranspiration by the crop factor.

How to Calculate Crop Water Use?

The following steps outline how to calculate Crop Water Use.

  1. First, determine the reference evapotranspiration (mm/day). 
  2. Next, determine the crop factor. 
  3. Next, gather the formula from above = Etc = Eto * Kc.
  4. Finally, calculate the Crop Water Use.
  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.

reference evapotranspiration (mm/day) = 284

crop factor = 113