Water Application Rate Calculator

Calculate water application rate, inches per hour, gallons per minute per acre, total gallons, acre-inches, runtime, and irrigation cost. Use this calculator for pivots, sprinklers, drip systems, and field irrigation planning.

Calculate Water Application Rate

Application Rate = Flow Rate GPM × 96.3 ÷ Field Acres.
Your result will appear here.

How the water application rate calculator works

Application rate:
Enter flow rate and field acres to estimate gross inches per hour and net inches per hour.

Runtime needed:
Enter target water depth to estimate how long the system should run.

Required flow rate:
Enter target depth and runtime to estimate the GPM needed to apply that water.

Application cost:
The calculator estimates water cost, energy cost, labor cost, setup cost, total cost, and cost per acre.

Why use a water application rate calculator?

A water application rate calculator helps estimate how quickly an irrigation system applies water across a field.

It can help compare flow rate, acres, application depth, runtime, system efficiency, distribution uniformity, total gallons, and irrigation cost.

What your result means

Your result shows estimated application rate, net application rate, GPM per acre, total gallons applied, acre-inches applied, water depth applied, runtime needed, required flow rate, and cost. These are estimates based on the values you enter.

Water application rate formulas

Frequently asked questions

How do you calculate water application rate?

Divide flow rate in gallons per minute by field acres to get GPM per acre. Then divide GPM per acre by 453 to estimate inches per hour.

How many GPM per acre equals one inch per day?

About 18.9 GPM per acre equals one inch per day. One GPM per acre applies about 0.053 inches per day, before efficiency adjustments.

How do you calculate water depth applied?

Multiply flow rate by runtime minutes to get gallons applied, divide by 27,154 to get acre-inches, then divide by field acres.

Why include system efficiency?

System efficiency estimates the share of pumped water that reaches the crop root zone. Lower efficiency reduces the net application rate.