Pump Head ⇄ Pressure
Convert a pressure to metres of head for a fluid, plus static lift.
Your recent runs (stored only in your browser)
No calculations yet — results land here so you can compare runs.
The engineering
Pumps are head machines, not pressure machines: a centrifugal pump lifts any fluid the same number of metres, so the pressure it develops scales with density. This card converts gauge pressure to head at SG × 1000 kg/m³ (water taken as exactly 1000 — the real 998 at 20 °C is a 0.2% quibble) and adds the static elevation term. 100 kPa of water is 10.2 m; the same 100 kPa of gasoline is 13.8 m.
This is the static piece of Total Dynamic Head only — friction losses through pipe and fittings (a Darcy–Weisbach job) and any velocity head are extra, and NPSH is its own separate conversation. The SG effect works both ways: a pump curve made on water delivers less *pressure* on gasoline but draws less power too.
Where this math comes from
That pressure is height in disguise was Torricelli's 1643 discovery — his mercury barometer literally measured the atmosphere in centimetres of fluid. Daniel Bernoulli's Hydrodynamica (1738) put pressure, velocity, and elevation into one conserved sum, and Euler's 1754 turbomachinery analysis showed a rotating impeller adds a fixed *head*, not a fixed pressure — the fact this card exists to exploit.
The Hydraulic Institute's pump-test standards in the twentieth century entrenched feet (and metres) of head as the pump industry's native unit, which is why every pump curve's vertical axis needs this conversion before it means anything in kPa.
- 1643Evangelista TorricelliThe barometer — pressure measured as fluid height.
- 1738Daniel BernoulliHydrodynamica — head, velocity, and pressure unified.
- 1754Leonhard EulerTurbomachine equation — pumps deliver head, not pressure (circa).
See the full timeline of the math behind every calculator →
Runs entirely in your browser — nothing you enter leaves this page. Your recent runs are stored only on your device.