Enter the crop coefficient, actual crop evapotranspiration, and reference evapotranspiration into the calculator to determine the missing variable.

Crop Coefficient Calculator

Kc by Crop
Solve Kc, ETc, ETo

Select a crop and growth stage to get a typical crop coefficient. Optionally enter reference evapotranspiration (ETo) to estimate ETc.

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Crop Coefficient Formula

The following formula is used to calculate the crop coefficient for a given actual crop evapotranspiration and reference evapotranspiration.

Kc = ETc / ETo

Variables:

  • Kc is the crop coefficient
  • ETc is the actual crop evapotranspiration
  • ETo is the reference evapotranspiration

To calculate the crop coefficient, divide the actual crop evapotranspiration by the reference evapotranspiration.

What is a Crop Coefficient?

A crop coefficient (Kc) is a factor used in agricultural water management to estimate the water requirements of different crops. It is used in conjunction with reference evapotranspiration (ETo) to determine the actual evapotranspiration (ETc) of a specific crop. The crop coefficient varies depending on the type of crop, its growth stage, and local climatic conditions. By using the crop coefficient, farmers and agricultural planners can make more accurate decisions about irrigation scheduling, ensuring that crops receive the optimal amount of water for healthy growth and maximum yield.

How to Calculate Crop Coefficient?

The following steps outline how to calculate the Crop Coefficient.

  1. First, determine the actual crop evapotranspiration (ETc).
  2. Next, determine the reference evapotranspiration (ETo).
  3. Finally, calculate the crop coefficient using the formula Kc = ETc / ETo.
  4. After inserting the values 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.

Actual Crop Evapotranspiration (ETc) = 5 mm/day

Reference Evapotranspiration (ETo) = 6 mm/day