How long should I run my drip irrigation?

Run time depends on emitter flow and how much water you want delivered, not a fixed clock. Decide a target volume for the bed, then this tool divides it by your system's total flow rate to give the exact minutes to run.

How is the run time calculated?

Total system flow is the single emitter rate multiplied by the number of emitters. Run time in minutes is your target volume divided by that flow, scaled to minutes. For example, 10 emitters at 1 GPH deliver 10 gallons per hour, so 5 gallons takes 30 minutes.

Should target volume be per plant or per zone?

Enter the total for the whole zone you are scheduling. If you know a per-plant need, multiply by the number of plants first. The tool also reports per-emitter delivery so you can check each plant gets a sensible amount.

Do emitter ratings stay accurate?

Pressure-compensating emitters hold close to their rated flow across a range of pressures, while non-compensating emitters vary with pressure and line length. If your emitters are not pressure-compensating, treat the result as an estimate and verify with a catch-cup test.

Can I mix GPH and LPH?

Pick one unit system and stay in it. Choose gallons or litres at the top, and enter both the emitter rate and the target volume in that same unit so the run time stays correct.

Drip Irrigation Run Time Calculator

A drip system should run long enough to deliver a chosen volume of water, not an arbitrary number of minutes. This calculator works out that run time from your emitter flow rate, the number of emitters, and the water volume you want to apply.

How it works

The system’s total flow is the emitter rate times the emitter count, and run time is the target volume divided by that flow:

system flow (per hour) = emitter flow × number of emitters
run time (minutes)     = target volume ÷ system flow × 60
per emitter delivered  = target volume ÷ number of emitters

So ten 1 GPH emitters deliver 10 gallons per hour; to apply 5 gallons you run the zone for 30 minutes, and each plant receives half a gallon.

Notes and tips

Pick gallons or litres and keep every input in that unit. Pressure-compensating emitters hold their rated flow well, so the calculation is reliable; with cheaper non-compensating emitters, confirm real output with a quick catch-cup test under a few drippers. Watering deeply and less often encourages deeper roots, so favour a longer run on fewer days over short daily bursts, and adjust the target volume up in heat and down in cool, wet spells.