Pressure

psitoftH₂O

Convert pounds-force per square inch (psi) to feet of water column (4 °C) (ftH₂O).

Factor1 psi = 2.306659 ftH₂O

Converter

Input

psi

Accepts numbers or expressions, e.g. 150 + 14.7

Result

115.333ftH₂O

Rendered to 6 significant figures.

Formula

ftH₂O = psi × 2.306659

Multiply any value in pounds-force per square inch by 2.306659 to obtain the value in feet of water column (4 °C).

Worked example

Convert 50 psi to ftH₂O.

01Start with 50 psi.
02Multiply by the conversion factor: 50 × 2.306659 = 115.333 ftH₂O.

Result50 psi = 115.333 ftH₂O

Conversion table

psi	ftH₂O
1	2.3067
2	4.6133
5	11.533
10	23.067
20	46.133
50	115.33
100	230.67
200	461.33
500	1153.3
1000	2306.7

Reference values rounded to 5 significant figures for display.

FAQ

What is the conversion factor from psi to ftH₂O?

1 psi equals 2.306659 ftH₂O. To convert, multiply the value in pounds-force per square inch by 2.306659.

How do I convert 1 psi to ftH₂O?

1 psi = 2.30666 ftH₂O. For any value, multiply by 2.306659.

How do I convert ftH₂O back to psi?

Divide by the same factor — or equivalently, multiply by 0.4335275. So 1 ftH₂O = 0.433528 psi.

When would I need to convert pound-force per square inch to foot of water column (4 °C)?

Pressure conversions between psi and ftH₂O are common when working with mixed-vendor instrumentation, when piping codes use different units to process datasheets, or when converting field readings into SI for hydraulic calculations.

Is the conversion exact?

The factor shown is precise to at least 7 significant figures. For most process-engineering work this is far better than instrument accuracy. For metrology or trade applications, refer to the relevant national standard (NIST, BIPM, ISO 80000).

Pump head & pressure context

This is a fixed water-column conversion. “Water column” units (m wc, ft wc) assume the density of water at a standard reference temperature, so the ratio between pressure and head here is constant. That assumption is exactly why this page is deterministic.

For any other fluid — brine, oil, slurry, or hot water — the head ↔ pressure relationship depends on the fluid density (ΔP = ρ × g × h). Use the SG/density-aware Head ↔ Pressure calculator for those cases rather than a fixed water-column factor.

Head ↔ Pressure Calculator →Pressure vs Head →What Is Pump Head? →Pump Sizing →