Drip Irrigation Calculator — Pipe & Dripper Layout

Total pipe = Row length × Number of rows. Drippers per row = Row length ÷ Spacing + 1 (the +1 counts the emitter at the very start of the run).

Total system flow = Drippers × Flow rate per dripper. This is how a drip system's demand is sized: the flow you need at the tap is simply the sum of every emitter's output.

Wetted area assumes rows are laid one dripper-spacing apart — the layout UK suppliers recommend so each 30 cm wetting cone overlaps its neighbour (e.g. 30 cm drippers ⇒ rows 30 cm apart). If you space rows wider than the drippers, enter a higher Watering Rate to compensate.

Run time = (Wetted area × Watering rate) ÷ System flow. The default 4 L/m² roughly matches a UK summer crop loss of ~4 mm/day (1 mm over 1 m² = 1 L), so a typical session lands in the usual 30–60 minute window.