Free calculator

Pump & irrigation flow rate calculator

A pump has to satisfy two demands — turning the reservoir over for oxygen and mixing, and feeding every emitter at once — and it has to do it at height, where its rated GPH has already fallen off.

System demands

Reservoir volumegalTurnovers per hour×/hRecirculating systems typically cycle the full reservoir 1–2× per hour.

Emitters / dripperscountFlow per emitterGPH

Vertical liftftWater surface in the reservoir up to the highest outlet.Friction allowanceftRule of thumb: ~1 ft per 10 ft of tubing run plus ~1 ft per sharp elbow or inline filter.

Result

Includes a 1.2× wear & clogging factor

Pump delivery needed at 6.0 ft of head

60GPH

= 227 L/h

Reservoir turnover demand

50GPH

Emitter demand

6GPH

The pump is sized to the larger of the two demands.

Check the pump's flow-at-height curve, not the headline GPH: it must still deliver 60 GPH at 6.0 ft. Max-head ratings mean zero flow at that height.

The friction allowance is a flat estimate, not a hydraulic calculation — long runs of narrow tubing, drip manifolds, and venturis can lose far more. When in doubt, one pump size up costs a few watts; an undersized pump starves the far emitters first, silently.

Now that the water moves — what's in it? Solve your nutrient recipe →