Irrigation Pump Discharge Calculator
Estimate the discharge of an irrigation pump from its power, total head and efficiency.
Hydraulic relation: Q (mยณ/h) = 367 ร power(kW) ร efficiency รท total head(m). Total head is suction lift + delivery height + friction losses. Real pumps run at 50โ70% overall (motor ร pump) efficiency.
Indicative planning figures based on published research averages. Local soil tests, varieties and weather change actual requirements โ confirm with your agronomist or extension officer.
Disclaimer: This tool is for general informational and estimation purposes only and is not professional financial, tax, accounting or legal advice. All figures are estimates โ verify with a qualified professional before making decisions. Read the full disclaimer.
Farmers and irrigation engineers use the free Irrigation Pump Discharge Calculator to get an accurate answer in seconds โ no formulas to remember, works offline in the field.
About Irrigation Pump Discharge Calculator
Sizing an irrigation pump โ or checking the one you have โ starts with the relationship between power, head and discharge. The water power needed rises with both the flow rate and the total head (the vertical lift plus friction losses), and real pump-and-motor sets only convert 50โ70% of input power to useful work. This tool rearranges the hydraulic power equation to estimate discharge in mยณ/h and L/s from your pump's rated power, the total head it works against, and its overall efficiency.
How to use Irrigation Pump Discharge Calculator
- 1Enter your system or field values into the inputs.
- 2Read the headline result and the supporting breakdown.
- 3Apply the guidance in the note to your irrigation plan.
Why use Irrigation Pump Discharge Calculator?
- โUses the standard, citable irrigation engineering formula
- โClear inputs with sensible defaults
- โInstant result with the working shown
- โFree, fully in-browser and private
Frequently asked questions
How do I calculate pump discharge from power?+
Use Q (mยณ/h) = 367 ร power(kW) ร efficiency รท total head(m). For example, a 5 kW pump at 60% efficiency against 30 m head delivers about 367 ร 5 ร 0.6 รท 30 โ 36.7 mยณ/h. Higher head or lower efficiency reduces discharge.
What is 'total head' for an irrigation pump?+
Total head is the sum of the suction lift (depth to water), the delivery height (how high you push water) and the friction losses in pipes and fittings โ all in metres. Friction losses grow with flow and pipe length, so undersized pipe quietly steals discharge.
Is this tool free and private?+
Yes โ free, no sign-up, and all calculation runs in your browser, so it works offline and your data never leaves the device.
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