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Pressure

psitomH₂O

Convert pounds-force per square inch (psi) to metres of water column (mH₂O).

Factor1 psi = 0.7030696 mH₂O

Converter

psi

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

Result
70.307mH₂O

Rendered to 6 significant figures.

Formula

Formula
mH₂O = psi × 0.7030696

Multiply any value in pounds-force per square inch by 0.7030696 to obtain the value in metres of water column.

Worked example

Convert 100 psi to mH₂O.

  1. 01Start with 100 psi.
  2. 02Multiply by the conversion factor: 100 × 0.7030696 = 70.307 mH₂O.
Result100 psi = 70.307 mH₂O

Conversion table

psimH₂O
10.70307
21.4061
53.5153
107.0307
2014.061
5035.153
10070.307
200140.61
500351.53
1000703.07

Reference values rounded to 5 significant figures for display.

FAQ

What is the conversion factor from psi to mH₂O?
1 psi equals 0.7030696 mH₂O. To convert, multiply the value in pounds-force per square inch by 0.7030696.
How do I convert 1 psi to mH₂O?
1 psi = 0.70307 mH₂O. For any value, multiply by 0.7030696.
How do I convert mH₂O back to psi?
Divide by the same factor — or equivalently, multiply by 1.422334. So 1 mH₂O = 1.42233 psi.
When would I need to convert pound-force per square inch to metre of water column?
Pressure conversions between psi and mH₂O 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 →

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