Calculate total pump/tank head from elevation and friction loss, converted to pressure.
How to Use the Water Head Calculator
Enter the "Elevation Height (m)" between the pump/source and the tank/outlet.
Enter any additional "Friction Loss (m)" from pipe resistance, or leave it at 0.
Click "Calculate" to see the total head and equivalent pressure.
How Total Head and Pressure Are Calculated
Total head (m) = Elevation height + Friction loss.
Pressure (bar) = Total head × 0.09804. A column of water one metre tall presses down with roughly 0.098 bar, so about 10.2 m of water equals 1 bar.
Pressure (psi) = bar × 14.5038.
The tool does not work out friction for you. You enter the friction loss in metres from a pipe chart, a friction loss calculation or a pump supplier's estimate, and it is added straight to the static height.
Worked Example: Pumping From a Sump to a Roof Tank
A G+3 house has its pump next to an underground sump. With storeys of roughly 3 m each plus a tank stand, the tank inlet sits about 15 m above the pump. Allowing 3 m for friction in the delivery pipe, bends and valves, total head = 15 + 3 = 18 m. Pressure = 18 × 0.09804 = 1.76 bar, or about 25.6 psi.
When choosing a pump, look at its performance curve or the head-and-flow table on its nameplate and check how many litres per minute it delivers at 18 m. A pump whose maximum head is only slightly above 18 m will deliver very little water at that height, so pick one where 18 m falls comfortably inside its working range.
Head to Pressure Reference
Head
Pressure (bar)
Pressure (psi)
Roughly equal to
3 m
0.29
4.27
One storey
5 m
0.49
7.11
Ground plus one floor
10 m
0.98
14.22
About 1 bar
15 m
1.47
21.33
Roof tank of a G+3 building
20 m
1.96
28.44
About 2 bar
30 m
2.94
42.66
Mid-rise apartment block
Practical Points
Measure the right height: For a pump, use the vertical distance from the water level in the sump or well to the point where water is discharged into the tank, not the length of the pipe. If the pump sits above the water it draws from, include that suction lift in the elevation.
Suction has a limit: A surface-mounted centrifugal pump can, in practice, lift water only about 6 to 7 m on the suction side, even though atmospheric pressure could in theory support around 10 m. For deeper water, a submersible or jet pump is used.
Gravity supply works the other way: The same conversion tells you the pressure at a tap fed from an overhead tank. A shower 2 m below the bottom of the tank gets only about 0.2 bar, which is why top-floor bathrooms often have weak showers and sometimes need a booster pump.
Friction grows quickly with flow: Long runs, small pipes and many elbows add friction, and the loss rises sharply as flow increases. If you are unsure, a larger delivery pipe usually reduces friction more cheaply than buying a bigger pump.
Frequently Asked Questions
Head is the equivalent height of a water column that represents a given pressure — here it combines the static elevation difference between the pump/source and the tank/outlet, plus any additional friction loss head from pipe resistance.
Pressure (bar) = Total Head (m) × 0.09804, since roughly 10.2 metres of water head equals 1 bar of pressure.
Pumps are rated by how much total head they can overcome. If your elevation + friction losses exceed the pump's rated head, it won't deliver adequate flow at the outlet.
No. Static head is only the vertical height difference. Total head adds the friction losses in pipes, bends and valves, and sometimes a required pressure at the outlet. A pump must be chosen for total head, which is why this tool lets you add friction to the elevation.
Multiply by about 10.2. For example, a pressure gauge reading of 1.5 bar corresponds to roughly 15.3 m of water head. To go the other way, divide metres by 10.2 or multiply by 0.098.