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Feet of Head to PSI Calculator

Convert a vertical water column in feet into pressure in psi, for pump selection and system pressure checks.

Computed in your browser — nothing you enter is uploaded. Figures are presented for United States against IRC 2024, and every formula is cited under regulatory standards below.

Last verified 2026-08-26 · v1.0.0

Market
Imperial · sales tax

Static pressure

43.35 psi

High confidence

1 ft of water at 4 °C = 62.428 lb/ft³ ÷ 144 in²/ft² ≈ 0.4335 psi. Equivalently, 2.31 ft per psi. Assumes clean water at 4 °C. For any other fluid, multiply by its specific gravity.

Head entered
100 ft
Pressure
43.35 psi
Metric equivalent
298.91 kPa
Bar
2.99 bar

Pumps are catalogued in feet of head; gauges and fixtures are rated in psi. Converting between them is the moment a pump curve becomes a check you can carry out with a gauge, and it is where a system that looked adequate on paper turns out to be 15 psi short at the top floor.

Add the equipment this sizes

This result is a specification — 43.353 psi — not a quantity. Put the thing it sizes into your project: how many, what you call it, and your supplier’s price.

Preliminary estimate, not certified engineering. This tool produces an indicative quantity calculation for planning purposes only — it is not a certified structural analysis, a guaranteed material takeoff, or a substitute for building department approval. Always verify measurements on-site and have a licensed contractor or structural engineer review any load-bearing, code-sensitive, or safety-critical work before purchasing materials or starting construction. Spotted an arithmetic or standards error? Report it to contact@craftquantities.com with your inputs — confirmed fixes become pinned regression tests.

[Schema Verified] Computed in alignment with American Concrete Institute (ACI 318-19) formulas and International Residential Code (IRC 2024) spatial boundaries.

Regulatory standards & verification citations

  • Water density 62.428 lb/ft³ at 4 °C — NIST/CRC standard reference
  • Hydrostatic pressure p = ρgh; 1 psi ≈ 2.31 ft of water column

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Frequently asked questions

Why 2.31 feet per psi and not 2.3?
2.31 comes from water at 4 °C, where it is densest. The rounder 2.3 is a jobsite shorthand. Over a 300 ft lift the difference is about 2 psi — immaterial for a domestic pump, and worth carrying properly on a tall building or a long rising main.
Does the pipe diameter change the pressure?
Not the static pressure. A column of water exerts pressure by its height alone, so a 1 in pipe and a 12 in pipe at the same height read the same. Diameter matters for flow and friction loss, which is a separate and often larger part of the pump's duty.
What about a liquid that is not water?
Scale by specific gravity. Glycol at 1.04 gives 4% more pressure per foot; diesel at about 0.85 gives 15% less. This calculator assumes water — using it for a heating system with a strong glycol charge will under-read.
Is this the pressure my pump needs to produce?
It is one part of it. Total dynamic head is static head plus friction loss through pipe, fittings and valves, plus any pressure required at the outlet. Sizing on static head alone is a common way to end up with a pump that will not deliver at the top of the building.