Calculator · Fluid Mechanics
Pressure Head Calculator
A pressure can be stated as the height of a fluid column that would produce it. That height is the pressure head, and it only means something once you say which fluid it is a head of.
Inputs
The head is a head of this fluid. Mercury at 13 546 kg/m³ gives a far shorter column than water.
Gauge pressure is measured relative to the ambient pressure, so 0 kPa means ambient. It may legitimately be negative. No atmospheric pressure is added anywhere in this calculation.
Results
Pressure head h = p/(ρg)
Head of the fluid at 1000 kg/m³, equivalent to a gauge pressure of 100.000 kPa.
| Pressure p | 100 kPa |
|---|---|
| Head h | 10.197 m |
| Pressure reference | Gauge |
Explore in the Lab
The head becomes a depth in the pressure field of the same fluid.
Technical reference
h = p / (ρ g)
p = ρ g h
- h
- pressure head, a height of the stated fluid[m]
- p
- pressure being expressed as a head[Pa]
- ρ
- density of the fluid the head is measured in[kg/m³]
- g
- gravity, 9.80665 m/s²[m/s²]
A head is always a head of a named fluid. The same pressure is about 10.2 m of water and about 0.75 m of mercury, so quoting a head without the fluid is meaningless.
A gauge pressure below ambient gives a negative head, which is a legitimate result: it means the level sits below the reference, not that the calculation failed.
This is the pressure term of the total head only. Elevation and velocity head belong to the energy equation and are not part of this calculator.