Irrigation Energy Cost Calculator

Calculate pumping energy cost from Total Dynamic Head, flow rate, pump and motor efficiency, and electricity or diesel prices.

Inputs

Flow rate (GPM)

Static lift (ft)

Friction loss (ft)

Operating pressure (PSI)

Pump efficiency (%)

Motor efficiency (%)

Electric rate ($/kWh)

Diesel price ($/gal)

Operating hours/season

Fuel type (0=Electric, 1=Diesel)

Tab to move between fields

Results

Total Dynamic Head (ft)

279

Cost per hour ($)

$6.34

Cost per acre-inch ($)

$3.59

Water horsepower (WHP)56.4

Brake horsepower (BHP)78.3

Power demand (kW)63.4

Overall plant efficiency (%)66.2

Cost per 1,000 gal ($)$0.13

Seasonal energy cost ($)$7,613.00

Seasonal energy (kWh)76,128

Seasonal diesel (gal)4,133

Capacity (acre-in/hr)1.77

How to Use This Calculator

Enter Flow rate (GPM), Static lift (ft), and Friction loss (ft).
Set Operating pressure (PSI), Pump efficiency (%), and Motor efficiency (%).
Adjust Electric rate ($/kWh), Diesel price ($/gal) as needed.
Review Total Dynamic Head (ft), Cost per hour ($) ($), and Cost per acre-inch ($) ($).
Use Water horsepower (WHP) and Brake horsepower (BHP) to inform your decision.

How the result changes with Static lift (ft)

Static lift (ft)	Total Dynamic Head (ft)	Cost per hour ($)	Cost per acre-inch ($)
50	179	$4.07	$2.30
175	304	$6.91	$3.91
325	454	$10.32	$5.84
450	579	$13.17	$7.45

What each input means

Flow rate (GPM): Pump discharge flow rate in gallons per minute.
Static lift (ft): Vertical distance from water source to discharge point.
Friction loss (ft): Head loss due to pipe friction (from friction loss tables).
Operating pressure (PSI): Required system operating pressure at the pivot or nozzles.
Pump efficiency (%): Pump efficiency from performance curve (typically 65-80%).
Motor efficiency (%): Electric motor efficiency (typically 88-95%).
Electric rate ($/kWh): Cost per kilowatt-hour of electricity.
Diesel price ($/gal): Cost per gallon of diesel fuel.
Operating hours/season: Total pump operating hours per irrigation season.
Fuel type (0=Electric, 1=Diesel): Select power source: 0 for electric, 1 for diesel.

What each result means

Total Dynamic Head (ft): Total head the pump must overcome (lift + friction + pressure).
Water horsepower (WHP): Theoretical power to move water (before efficiency losses).
Brake horsepower (BHP): Actual power required at the pump shaft.
Power demand (kW): Electrical power demand including motor efficiency.
Overall plant efficiency (%): Combined pump and motor efficiency.
Cost per hour ($): Energy cost per hour of pumping.
Cost per acre-inch ($): Energy cost to pump one acre-inch of water.
Cost per 1,000 gal ($): Energy cost per 1,000 gallons pumped.
Seasonal energy cost ($): Total energy cost for the irrigation season.
Seasonal energy (kWh): Total electricity consumed per season.
Seasonal diesel (gal): Total diesel fuel consumed per season.
Capacity (acre-in/hr): Water delivery capacity in acre-inches per hour.

How this is calculated

Worked example, using the default values

Identify Input Parameters
4 parameters
Flow rate (GPM) = 800, Static lift (ft) = 150, Friction loss (ft) = 25, Operating pressure (PSI) = 45 = 10 input(s) provided
Calculate Total Dynamic Head
Total Dynamic Head = staticLiftFt + frictionLossFt + pressureFt
279 = 279
Calculate Cost per hour
6.34 = $6.34
Calculate Cost per acre-inch
3.59 = $3.59
Calculate Water horsepower
Water horsepower = (flowRateGpm * tdh) / 3960
56.4 = 56.4
Calculate Brake horsepower
Brake horsepower = whp / pumpEff
78.3 = 78.3

Engine last updated July 26, 2026. Checked against 2 independently-derived tests — how we verify calculators.

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