Drip Irrigation Calculator
Calculate total drip system flow and how many gallons your emitters deliver per run, per day and per week.
How it works
System flow = emitters × flow per emitter (gal/hr) · Water per run = system flow × (run time ÷ 60) · Water per week = per run × days
A drip system’s flow is simply the number of emitters times each emitter’s rated output, usually given in gallons per hour. Multiplying by the run time gives the water delivered each cycle, and by the days per week gives the weekly total — useful for water bills and for checking the system stays within your supply’s flow limit. Converting to gallons per minute helps confirm your line and pressure regulator can keep up.
Worked example
20 emitters rated at 1 gph total 20 gal/hr (0.33 gal/min). Running 60 minutes delivers 20 × (60 ÷ 60) = 20 gallons per cycle; three cycles a week is 60 gallons.
Frequently asked questions
How long should I run drip irrigation?
Long enough to wet the root zone without runoff — often 30–60 minutes a few times a week for beds, adjusting for soil and weather. Sandy soil needs shorter, more frequent runs; clay needs longer, less frequent ones.
Will my hose supply enough flow?
Add up the emitter flows and compare to your supply. A typical outdoor spigot delivers several gallons per minute, but long runs and many emitters can exceed what one zone can pressurize — split large systems into zones if the total is high.
Why use drip instead of a sprinkler?
Drip delivers water straight to the root zone with very little evaporation or runoff, often using 30–50% less water than sprinklers while keeping foliage dry, which reduces disease.
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This calculator is for educational purposes. Double-check important results before acting on them.