Irrigation hydraulics
Garden Pump Total Dynamic Head Calculator
Combine elevation, required outlet pressure and estimated pipe losses to size a garden irrigation pump more realistically.
What total dynamic head includes
Total dynamic head combines vertical elevation, pressure required at the outlet and resistance through pipe, filters, valves and fittings. The calculator converts required psi to feet of water using 2.31 feet per psi, then adds the remaining head components and the selected allowance.
Head alone is not enough to select a pump. The pump must deliver the required gallons per minute at that head on its published performance curve. A high free-flow rating does not prove that a pump will supply the same flow after elevation and pressure are added.
Measure from operating water level
For a tank or pond, measure lift from the operating water surface to the highest delivery point. For a well, pumping water level matters more than static water level. Estimate pipe loss using actual pipe inside diameter, flow and developed length.
Pair this result with the garden water demand calculator and solar irrigation pump guide.
Frequently asked questions
Is TDH the same as vertical lift?
No. Lift is only one component.
Can I add a safety margin twice?
Avoid doing so. Enter realistic component losses and one deliberate allowance.
Why does pipe diameter matter?
Smaller pipe generally produces greater friction loss at the same flow.
Technical reference: Oklahoma State Extension describes elevation, piping resistance and end-use pressure as TDH components.