Water Pressure Calculator
Estimate water pressure from elevation, convert pressure to water head, and calculate the pressure available at a fixture.
Choose a calculation mode and enter your measurements. Results are estimates for water under static or simplified system conditions.
Pressure and Head Conversion
Static Pressure from Elevation
Available Pressure at a Fixture
Pressure and Head
Uses the approximate relationship 0.433 psi per foot of water head.
How to Use the Calculator
- Select US / Imperial or SI / Metric units, then choose one of the three calculation modes.
- For pressure/head conversion, choose the conversion direction and enter the pressure or water head.
- For static pressure, enter the elevation difference and select whether the point is above or below the source. Supply pressure is optional.
- For available fixture pressure, enter source pressure, elevation difference, direction, and estimated total pressure losses.
- Results update automatically when you change an input, calculation mode, or unit system. Use Reset Calculator to restore the defaults.
Assumptions and Limitations
This calculator assumes fresh water and uses approximate hydrostatic relationships: about 0.433 psi per foot of water head or 9.8 kPa per meter. Elevation above the source reduces pressure; elevation below the source increases it. The fixture mode subtracts the total pressure loss you enter. Actual operating pressure can vary with flow, pipe size, fittings, valves, pumps, temperature, and system conditions. This is an estimate, not a substitute for measuring pressure or checking local plumbing requirements. A negative calculated fixture pressure indicates insufficient available pressure under the entered assumptions.
