Pivot Irrigation Calculator

Calculate center pivot coverage area, application depth, GPM/acre, and peak demand capacity.

Pivot length (ft)

End gun throw (ft)

System flow (GPM)

Revolution time (hrs)

Application efficiency (%)

Peak crop ET (in/day)

Tab to move between fields

Total area (acres)

125.7

Application depth (in)

1.01

Base area (acres)125.7

End gun area (acres)0

Daily capacity (in/day)0.34

GPM per acre6.37

Outer tower speed (ft/min)1.92

Meets peak demand (1=yes)0

Gross Application (in)1.06

How to Use This Calculator

Enter pivot length in feet from center to last tower (1/4 mile = 1,320 ft).
Set system flow rate in GPM and revolution time in hours.
Enter end gun throw distance in feet (0 if no end gun).
Input application efficiency (%) and peak crop ET in inches per day.
Review Total area (acres), Application depth (in/revolution), and whether the system meets peak demand.

How the result changes with Pivot length (ft)

Pivot length (ft): Length from pivot point to last tower. Quarter mile = 1,320 ft.
End gun throw (ft): Additional radius covered by end gun. 0 if no end gun.
System flow (GPM): Total system flow rate in gallons per minute.
Revolution time (hrs): Time for one full revolution. Typical: 12-96 hours.
Application efficiency (%): Water application efficiency. LEPA=95%, sprinkler=80-85%.
Peak crop ET (in/day): Peak daily crop evapotranspiration demand.

Base area (acres): Irrigated area without end gun.
Total area (acres): Total irrigated area including end gun coverage.
End gun area (acres): Additional area from end gun.
Application depth (in): Inches of water applied per revolution.
Daily capacity (in/day): Maximum daily application at continuous operation.
GPM per acre: System capacity index. Typical target: 4-6 GPM/acre.
Outer tower speed (ft/min): Speed of the outermost tower.
Meets peak demand (1=yes): Whether system capacity exceeds peak ET requirement.

Identify Input Parameters
4 parameters
Pivot length (ft) = 1320, End gun throw (ft) = 0, System flow (GPM) = 800, Revolution time (hrs) = 72 = 6 input(s) provided
Calculate Total area
Total area = totalAreaFt2 / sqFtPerAcre
125.7 = 125.7
Calculate Application depth
Application depth = (totalVolumeGal * 231) / (totalAreaFt2 * 144)
1.013 = 1.013
Calculate Base area
Base area = baseAreaFt2 / sqFtPerAcre
125.7 = 125.7
Calculate End gun area
End gun area = totalAreaAcres - baseAreaAcres
0 = 0