For water with specific gravity (SG) approximately 1, pressure head in feet is approximately PSI × 2.31. The reverse calculation is PSI = head in feet ÷ 2.31. These calculators convert pressure difference and equivalent water head; a single pressure reading does not establish a complete system TDH.
PSI to pressure head
Pressure head to PSI
What this calculator includes
The tool assumes SG = 1 and uses a rounded conversion factor. Its result is a pressure-head conversion. It does not calculate pipe friction, elevation changes or velocity-head differences, and it does not select a pump model.
For a liquid with a different specific gravity, use H (ft) ≈ Δp (psi) × 2.31 / SG, or Δp (psi) ≈ H (ft) × SG / 2.31. Use the specific gravity for the actual liquid and temperature. The input fields above do not apply an SG correction.
Pressure head and total dynamic head
Pressure head is one component of the energy balance. KSB's pressure-head reference distinguishes it from the velocity and elevation terms used in total head.
Across pump inlet and outlet measurement points, pump total head includes the pressure difference divided by fluid density and gravity, the velocity-head difference and the elevation difference. Keep both pressure readings on the same reference basis. When calculating the head required between other system boundaries, include the applicable piping losses; avoid counting the same loss twice.
For a pump-duty review, report inlet and outlet pressures separately and identify the measurement locations. The RO high-pressure pump specification guide shows the other information needed to compare a supported operating point.
Worked conversion for water
At SG = 1, a pressure difference of 50 psi corresponds to approximately 115.50 ft of pressure head. Entering 115.50 ft in the reverse calculator returns 50.00 psi. This is an illustrative unit conversion, not a Rohre pump rating or a system sizing result.
Use the result in a pump enquiry
Review the RO pump range for available product families. Include the required flow, inlet and outlet pressures, water type and temperature in the Pump Selection Form. Keep the pressure units and reference basis with every value.
The RO engineering resource center provides other engineering documents and calculation tools. Review each tool's assumptions before using its output in a selection record.
