What is evapotranspiration (ET)?

ET is the combined water loss from soil evaporation and plant transpiration. It determines how much water crops need daily.

How much water is an acre-inch?

One acre-inch equals 27,154 gallons — enough water to cover one acre one inch deep.

Irrigation & Water

Calculate daily and weekly irrigation water needs based on crop evapotranspiration and system efficiency.

Fill in the fields below, then click Calculate.

Field Size

acres

Daily ET Rate

inches/day

Evapotranspiration rate from weather station or estimate

System Efficiency

Weekly Rainfall

inches

No results yet

Fill in the fields and click Calculate to see results.

Check local weather station data for daily ET rates.
Peak ET rates in summer can reach 0.3-0.4 inches/day for many crops.
Schedule irrigation based on soil moisture monitoring, not just calendar.
Deficit irrigation can save water without significant yield loss for some crops.