Pump Total Dynamic Head (TDH) Calculator
Add up the total dynamic head (TDH) a pump must overcome: static lift, friction losses, discharge/pressure head and velocity head. TDH is the head figure you take to the pump curve to select a pump and set its duty point for a dewatering or transfer line.
Enter Values
Before you rely on this: First-pass guide only. Verify safety-critical or regulated work against the relevant standards, your project requirements and a qualified professional.
How to use this calculator
- Enter the static lift in metres (vertical rise from water surface to discharge point).
- Enter the friction head loss in metres for the pipe and fittings at the design flow.
- Optionally add discharge/pressure head and velocity head (each defaults to 0), then read the total dynamic head.
How it works
TDH = static lift + friction head loss + discharge (pressure) head + velocity head. Static lift is the geometric rise, friction covers pipe and fitting losses, discharge head is any pressure needed at the outlet, and velocity head is the kinetic term v²/2g. The sum is the head the pump must deliver at the design flow.
Worked example
Worked example. Static lift 30 m, friction 8 m, discharge head 5 m and velocity head 0.5 m give TDH = 30 + 8 + 5 + 0.5 = 43.5 m. With only static 25 m and friction 10 m, TDH = 35 m.
Common mistakes
- Guessing friction head instead of computing it for the real pipe size, length, flow and fittings.
- Forgetting valve and fitting (minor) losses, which can rival straight-pipe friction on short lines.
- Leaving out required discharge pressure at the outlet (e.g. a sprinkler or elevated tank) when it is significant.
Frequently asked questions
Is TDH the same as static head?
No. Static head is only the vertical lift. TDH adds friction, discharge pressure and velocity head, so it is always at least as large as the static lift.
Can I ignore velocity head?
Often, yes — velocity head is usually small for typical pipe velocities, so it is optional here and defaults to zero. Include it when velocities are high or precision matters.
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Tip: Enter any known values to calculate the remaining results.
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