How to use this calculator
Count the emitters operating together and use their rated flow in liters per hour. Enter the actual run time for one watering session. For different emitter types, calculate each group separately and add the totals.
The formula
A worked example
24 emitters rated at 2 L/h deliver 48 liters per hour. Running them for 45 minutes delivers an estimated 36 liters.
Assumptions & limitations
Assumes all emitters flow at the entered rate for the whole session. Pressure, clogs, leaks, and uneven supply can change delivery. This does not determine how much water a crop needs.
Common questions
My emitters are labeled in gallons per hour. What should I enter?
Convert U.S. gallons per hour to liters per hour by multiplying by 3.785411784. Imperial gallons use a different conversion.
Does this recommend a watering schedule?
No. It calculates water delivered; plant needs depend on soil, weather, crop, and growing stage.
Supporting reference
The method above states this calculator’s assumptions. This reference provides related definitions and technical context.
Utah State University: backyard drip irrigation ↗Formula and worked example checked against automated test cases. About our methodology.