Irrigation Runtime Calculator

Calculate how long to run irrigation based on acres, water depth, flow rate, system efficiency, and total gallons needed. Use this irrigation runtime calculator for pivots, sprinklers, drip systems, flood irrigation, and crop watering schedules.

Calculate Irrigation Runtime

Runtime Hours = Total Gallons Needed ÷ Flow Rate GPM ÷ 60.
Your result will appear here.

How the irrigation runtime calculator works

Runtime from flow rate:
Enter acres, water depth, system efficiency, and flow rate to estimate how many hours irrigation should run.

Flow rate from runtime:
Enter available runtime hours to estimate the gallons per minute needed to finish the irrigation set.

Water depth from runtime:
Enter flow rate and runtime to estimate the water depth applied over the field.

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

Why use an irrigation runtime calculator?

An irrigation runtime calculator helps estimate how long an irrigation system needs to run to apply a target water depth.

It can help compare field acres, water depth, flow rate, system efficiency, operating hours, total gallons, and irrigation cost.

What your result means

Your result shows estimated runtime hours, runtime days, total gallons, acre-inches, acre-feet, required flow rate, applied water depth, water cost, energy cost, labor cost, and total cost. These are estimates based on the values you enter.

Irrigation runtime calculator formulas

Frequently asked questions

How do you calculate irrigation runtime?

Calculate total gallons needed, then divide by flow rate in gallons per minute and divide by 60. This converts minutes into runtime hours.

How many gallons are in one acre-inch?

One acre-inch of water is about 27,154 gallons. This means applying one inch of water to 40 acres requires about 1,086,160 gallons before efficiency adjustments.

Why does system efficiency affect runtime?

System efficiency accounts for water that does not reach the crop root zone. Lower efficiency means the system must pump more gross water to apply the same useful water depth.

How do I calculate required GPM?

Divide total gallons needed by the available runtime hours, then divide by 60. This estimates the flow rate needed to finish within the available time.