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Drip Irrigation Flow Calculator

Work out drip irrigation flow instantly with clear inputs, formula shown and shareable results.

About Drip Irrigation Flow Calculator

Drip system flow is simply emitter count times emitter rate: 250 emitters at 4 L/h is 1000 L/h, or 0.28 L/s, applying 1500 litres over a 90 minute run. The pump and mainline must supply that flow at the emitters' rated pressure, usually around 1-2 bar for pressure-compensating drippers.

Formulas

System flow

flow = number of emitters x rate per emitter

Water applied

volume = flow x run hours

Worked example

With the default values below, Drip Irrigation Flow Calculator returns Total System Flow of 1,000. Change any input above and every figure here is recalculated in your browser.

Inputs used

Number of emittersminimum 0
250
Flow per emitterminimum 0 L/h
4 L/h
Run timeminimum 0 h
1.5 h

Results

Total System Flow
1,000 L/h
Same Flow In Litres Per Second
0.2778
Water Applied Per Run
1,500 L
Flow In Cubic Metres Per Hour
1.000

Step by step

  1. 1Values used
  2. 2System flow
  3. 3Water applied
  4. 4Total System Flow= 1,000 L/h
  5. 5Same Flow In Litres Per Second= 0.2778
  6. 6Water Applied Per Run= 1,500 L
  7. 7Flow In Cubic Metres Per Hour= 1.000

Assumptions and limits

  • The result is derived only from the 3 inputs listed above. Anything not among them is not part of the calculation.
  • In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
  • Figures are rounded for display to 4 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

Why use pressure-compensating emitters?

Because pressure falls along a lateral, so ordinary emitters deliver less at the far end. Compensating types hold rate across a pressure band.

How do I know how long to run the system?

Match the applied depth to crop evapotranspiration. Applied litres divided by wetted area gives the equivalent millimetres of rain.

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