Irrigation Water Calculator

Common irrigation flow meter units include Gallons x 100, Gallons x 1000, Acre-Feet x 0.001, and Acre-Inches x 0.01. The units are usually displayed just below the rolling numbers on your meter, similar to an odometer.

Note the meter reading at the beginning of irrigation (when you turn on the system) and at the end (when irrigation stops). Enter only the numbers visible on the totalizer display, without decimals.

If your meter has rolled over (reset to zero), you may need to add the maximum reading value to your ending reading or enter a 1 in front of the ending reading to make calculations work correctly.

Most crops need 1-2 inches of water per week, including rainfall. Cool-season grasses need about 1 inch per week, while warm-season crops may need 1.5-2 inches during peak growing season.

Application rates should match your soil's infiltration rate to avoid runoff. Sandy soils can handle 0.5-1.0 inches per hour, while clay soils typically handle 0.1-0.3 inches per hour.

One acre-inch equals 27,154 gallons. One acre-foot equals 325,851 gallons or 12 acre-inches. These conversions help compare water usage across different measurement systems.

Accurate water measurement helps optimize crop yields, reduce water waste, manage irrigation costs, and comply with water use regulations. It also helps identify system inefficiencies.

Check water usage weekly during growing season to ensure you're applying the right amount. Daily monitoring is recommended during hot, dry periods or when establishing new crops.