Crop Coefficient Calculator

Calculate growth-stage Kc values and crop ET using FAO-56 methodology for irrigation scheduling.

Reference ET (in/day)

Kc initial

Kc mid-season

Kc end

Initial stage (days)

Development stage (days)

Mid-season stage (days)

Late season (days)

Current day of season

Tab to move between fields

Current Kc

1.15

Crop ET (in/day)

0.29

Growth stage (1-4)2

Crop ET (mm/day)7.3

Season avg Kc0.79

Seasonal ETc (in)24.6

Total season (days)125

Daily water (gal/acre)7,807

Stage NameDevelopment

How to Use This Calculator

Enter reference ET (ETo) in inches per day from a local weather station or Blaney-Criddle calculation.
Input Kc initial, mid-season, and end values for your crop from FAO-56 tables.
Set growth stage durations: initial, development, mid-season, and late season days.
Enter the current day of season to get today's interpolated Kc and crop ET.
Read Crop ET (in/day), Season average Kc, and Seasonal ETc to plan irrigation scheduling.

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