Pump TDH Calculator
Static · formula-only · worked example computed when this page was built · no live data
The Pump TDH Calculator sizes a pump and motor from Total Dynamic Head (TDH) = static head + friction head + velocity head. Example: for a 200 L/min pump lifting water 15 m through 60 m of 50 mm PVC pipe, at 30 °C fluid temperature, at 90% motor efficiency, Total Dynamic Head = 18.12 m, Pipe velocity = 1.54 m/s, Recommended motor = 1.1 kW, NPSH available = 9.44 m (per ISO 9906 | PSME Code | ASHRAE 2021 Ch.22).
How it works
TDH = H_static + H_friction + H_velocity, where friction head uses Darcy–Weisbach with the Colebrook–White friction factor and real water properties at the operating temperature. Anything the worked example does not state uses this calculator's standard default; the interactive version shows every input and lets you change it.
Worked example (Plumbing & Pumps)
Inputs: a 200 L/min pump lifting water 15 m through 60 m of 50 mm PVC pipe, at 30 °C fluid temperature, at 90% motor efficiency.
| Result | Value |
|---|---|
| Total Dynamic Head | 18.12 m |
| Pipe velocity | 1.54 m/s |
| Recommended motor | 1.1 kW |
| NPSH available | 9.44 m |
Computed by WorkHive's calculation engine when this page was built; standard: ISO 9906 | PSME Code | ASHRAE 2021 Ch.22.
How to use this calculator
- Read the worked example. It uses a 200 L/min pump lifting water 15 m through 60 m of 50 mm PVC pipe, at 30 °C fluid temperature, at 90% motor efficiency and shows every number in the method.
- Follow the formula with your own figures: it returns Total Dynamic Head, Pipe velocity, Recommended motor, NPSH available, computed per ISO 9906 | PSME Code | ASHRAE 2021 Ch.22.
- To compute interactively, open the Pump TDH Calculator inside WorkHive's free Engineering Design suite (link below). It runs the same method with your inputs.
FAQ
What is total dynamic head (TDH)?
TDH is the total equivalent height a pump must overcome: the static lift plus friction losses in the pipe plus the velocity head. It sets the pump and motor size.
How do I calculate pump head?
Add static head + friction head + velocity head. Friction head comes from the Darcy–Weisbach equation using the Colebrook–White friction factor for the pipe material and flow.
What motor size do I need for a 200 L/min pump?
For a typical 200 L/min duty at ~18 m TDH, a 1.1 kW (1.5 HP) motor is usually enough after applying pump and motor efficiency and a service-factor margin. Always confirm against the manufacturer curve.
What is NPSH available and why does it matter?
NPSH available is the suction-side pressure margin before cavitation. It must exceed the pump's NPSH required, or the pump cavitates and wears out. It falls with elevation and hot water.
Run it on your own numbers
Open the interactive Pump TDH Calculator in WorkHive. Free, and a free sign-up saves your calculations, BOMs and scope-of-works to your account.