Irrigation Water Depth Calculator
Fill in the values and the answer updates as you type.
How the Irrigation Water Depth Calculator works
One acre-inch is the water needed to cover one acre one inch deep, which is 27,154 US gallons. Gallons pumped = flow × 60 × hours, and gross depth = gallons ÷ 27,154 ÷ acres. Net depth = gross depth × application efficiency, since wind, evaporation, runoff, and uneven spread waste some water. Sprinkler systems often reach 70 to 85% and drip systems 90% or more. Compare the net depth with the crop water use for the week to decide how long to run. Example: with Pump flow 800 gal/min, Hours of running 12 h, Area irrigated 20 acres, and Application efficiency 85 %, the result is Net depth reaching the crop (in) = 0.9; Gross depth pumped (in) = 1.06; Acre-inches pumped = 21.2.
Inputs and results
The Irrigation Water Depth Calculator takes 4 inputs and gives 5 results.
What you enter
- Pump flow (gal/min) — starts at 800.
- Hours of running (h) — starts at 12.
- Area irrigated (acres) — starts at 20.
- Application efficiency (%) — starts at 85.
What you get
- Net depth reaching the crop (in)
- Gross depth pumped (in)
- Acre-inches pumped
- Gallons pumped
- Hours to apply 1 gross inch
Example: Irrigation Water Depth Calculator with the starting values
With pump flow 800 gal/min, hours of running 12 h, area irrigated 20 acres and application efficiency 85 %, the calculator returns:
| Net depth reaching the crop (in) | 0.9 |
|---|---|
| Gross depth pumped (in) | 1.06 |
| Acre-inches pumped | 21.2 |
| Gallons pumped | 576,000 |
| Hours to apply 1 gross inch | 11.3 |
Change any value above and the results update straight away.
Irrigation Water Depth Calculator FAQ
How do I use the Irrigation Water Depth Calculator?
Enter pump flow, hours of running, area irrigated and application efficiency in the fields, then read net depth reaching the crop (in), gross depth pumped (in), acre-inches pumped and gallons pumped in the result panel. The answer updates as you type, and you can press Calculate or Enter to refresh it. Use “Copy link” to share your exact numbers with someone else.
What does the Irrigation Water Depth Calculator calculate?
Inches of water applied from pump flow, run time, and area. It returns net depth reaching the crop (in), gross depth pumped (in), acre-inches pumped and gallons pumped from the 4 values you provide.
What values does the Irrigation Water Depth Calculator start with?
It opens with pump flow 800 gal/min, hours of running 12 h, area irrigated 20 acres and application efficiency 85 % so you can see a working result straight away. Replace them with your own numbers, or press Reset to return to these starting values.
Is the Irrigation Water Depth Calculator free and private?
Yes. It is free, needs no account, and runs in your browser, so nothing you type is sent to or stored on our servers. See the Privacy Policy for details.
Can I rely on the Irrigation Water Depth Calculator for important decisions?
Treat the result as a well-rounded estimate. Real situations often have details a general calculator cannot know, so confirm important decisions with a qualified professional. See the Disclaimer for more.