Pump Capacity Calculator

Calculate irrigation pump capacity, gallons per minute, gallons per hour, acre-inches per day, pump horsepower, total head, pressure, runtime, and pumping cost. Use this pump capacity calculator for irrigation wells, transfer pumps, pivots, sprinklers, and farm water systems.

Calculate Pump Capacity

Water Horsepower = Flow Rate GPM × Total Head Feet ÷ 3,960.
Your result will appear here.

How the pump capacity calculator works

Pump capacity:
Enter flow rate to estimate gallons per hour, gallons per day, acre-inches per day, and GPM per acre.

Required horsepower:
Enter flow rate, total head, pump efficiency, and motor efficiency to estimate water horsepower and brake horsepower.

Runtime from capacity:
Enter field acres and target water depth to estimate how long the pump must run to apply the target irrigation depth.

Pumping cost:
The calculator estimates energy use, energy cost, labor cost, fixed cost, total cost, and cost per acre.

Why use a pump capacity calculator?

A pump capacity calculator helps estimate whether a pump can deliver enough water for the field, crop water need, and irrigation schedule.

It can help compare GPM, acres covered, water depth, runtime, total head, pressure, horsepower, energy use, and pumping cost.

What your result means

Your result shows estimated pump capacity, gallons per hour, gallons per day, acre-inches per day, GPM per acre, required horsepower, runtime, energy use, energy cost, total pumping cost, and cost per acre. These are estimates based on the values you enter.

Pump capacity calculator formulas

Frequently asked questions

How do you calculate pump capacity?

Pump capacity is commonly measured in gallons per minute. Multiply GPM by runtime minutes to estimate total gallons pumped.

How do you calculate pump horsepower?

Multiply flow rate in GPM by total head in feet, then divide by 3,960 to estimate water horsepower. Divide by pump and motor efficiency to estimate required input horsepower.

How many gallons are in an acre-inch?

One acre-inch is about 27,154 gallons. This is the amount of water needed to cover one acre with one inch of water.

What affects pump capacity?

Pump capacity can be affected by pump size, motor size, well output, total head, pipe friction, pressure, elevation, suction conditions, pump wear, and system restrictions.