Convert HEAD to PSI, Free
Type any HEAD value and see the PSI result instantly. No button press needed.
How to convert HEAD to PSI
Head pressure and PSI (pounds per square inch) are both measurements of pressure used in fluid systems, but they express that pressure differently. Head pressure is measured in feet or meters of fluid column height, while PSI is a direct pressure measurement. To convert feet of water head to PSI, multiply by 0.4335. So 100 feet of head equals 43.35 PSI at standard water density.
This conversion is commonly needed in plumbing, pump selection, irrigation system design, and water supply engineering. Pump curves are often specified in feet of head, while pipe pressure ratings and municipal water specifications use PSI. This converter handles water head (fresh water at standard density); for other fluids, the conversion factor differs based on specific gravity.
Enter your head value in feet
Type the head pressure in feet of water into the input field. Decimal values are accepted.
Read the PSI result
The equivalent pressure in PSI appears instantly. The conversion uses the standard factor for fresh water at room temperature.
Use the result in your design
Copy the PSI value for use in pump specifications, pipe pressure calculations, or equipment selection.
Frequently asked questions
What is the formula to convert head to PSI?
For fresh water: PSI = head (feet) x 0.4335. This is derived from the weight density of water (62.4 lb/ft3) divided by 144 (square inches per square foot). So 1 foot of water head equals 0.4335 PSI.
Does this work for fluids other than water?
No, this converter assumes fresh water at standard density. For other fluids, multiply the result by the fluid's specific gravity. Salt water, for example, has a specific gravity of about 1.025, so a 100-foot column of seawater creates slightly more pressure than fresh water.
What if my head is in meters, not feet?
Convert meters to feet first by multiplying by 3.28084, then use this tool. Alternatively, for meters of water head to PSI, multiply by 1.4223.
Why are pump curves listed in feet of head instead of PSI?
Head in feet is independent of the fluid's density, making it easier to compare pumps across different applications. PSI depends on the specific fluid being pumped.
Is this accurate for engineering calculations?
The conversion uses the standard water density factor and is accurate to four significant figures, sufficient for most pump selection and plumbing design work.