PSI to Head Converter

Pressure and head are the same thing in different units

A pump is rated in feet of head. A gauge reads in psi. A specification sheet may use either, and they describe the same physical quantity: the height of a column of fluid that a given pressure will support. This converter moves between them in both directions and adjusts for the fluid involved.

It is a working tool for pump selection and commissioning, HVAC and hydronic system design, irrigation layout, plumbing, and anyone reconciling a field gauge reading against a manufacturer’s curve.

The constant, and where it comes from

For water at 60 °F, 1 psi supports 2.309 feet of head. The derivation is straightforward: pressure is force per unit area, so a column of water one foot high exerts its own weight over its base. Water at 60 °F weighs 62.37 pounds per cubic foot, and there are 144 square inches in a square foot, so one psi corresponds to 144 ÷ 62.37 = 2.3088 feet — 2.309 to the precision this tool uses.

For any other fluid, divide by its specific gravity: head in feet = psi × 2.309 ÷ SG. A denser fluid needs a shorter column to produce the same pressure, and a lighter one needs a taller column.

Worked conversions, both directions

Sixty psi of water at 60 °F is 138.54 feet of head. Run the same 60 psi through other fluids and the answer moves with density: seawater at a specific gravity of 1.025 gives 135.16 feet, a 50% propylene glycol mix at 1.043 gives 132.83 feet, and diesel at 0.85 gives 162.99 feet.

Going the other way, 100 feet of water head is 43.31 psi, and a 30-foot static lift is 12.99 psi — which is the quick check that tells you whether a pump has any margin left at the top of a building.

The per-psi figure is worth memorising in the form you use most: 2.309 feet per psi for water, 2.253 for seawater, 2.716 for diesel.

Static head only — what is missing

This converts static head: the pressure due to elevation alone. A real system has more to overcome, and a pump sized on static head alone will be undersized.

• Friction loss along the pipe, which rises roughly with the square of flow rate and depends on pipe diameter, material and age.
• Minor losses at elbows, tees, valves and strainers, usually accounted for as an equivalent length of straight pipe.
• Velocity head, the kinetic energy of the moving fluid, which is small in most systems but not always negligible.
• Suction conditions and NPSH, which decide whether the pump cavitates rather than how high it can push.

Total dynamic head is static head plus all of those. The figure this tool produces is the first term.