Pressure

Inches of Water to PSI

Convert inches of water to psi instantly. 1 inH2O = 0.0361272905 psi. Includes the exact factor, a conversion table of common values and the definition of both units.

inH2O
PSI
One step, one exact factorInches of Waterwhat you have× 0.0361272905PSIwhat you getBoth units are defined against the same base unit, so the factor is exact — never an approximation.

How to convert inches of water to psi

To convert inches of water to psi, divide by 27.6799058214 (multiply by 0.0361272905). The relationship is fixed, so the same factor works for any quantity — there is nothing to look up and nothing that changes with temperature, location or context.

psi = inH2O × 0.0361272905

Inches of Water to PSI conversion table

The values people look up most often, rounded for reading. Use the calculator above for anything in between.

Inches of WaterPSI
1 inH2O0.036127 psi
2 inH2O0.072255 psi
3 inH2O0.108382 psi
5 inH2O0.180636 psi
10 inH2O0.361273 psi
20 inH2O0.722546 psi
25 inH2O0.903182 psi
50 inH2O1.806365 psi
100 inH2O3.612729 psi
500 inH2O18.063645 psi
1,000 inH2O36.127291 psi

What is a inches of water?

A low-pressure unit used for ventilation and gas appliances.

What is a psi?

Pounds per square inch, the US pressure unit for tyres and plumbing.

The formula

psi = inH2O × 0.0361272905

Every result on this page comes from this formula. Nothing is rounded until the final display, so figures match a spreadsheet to the cent.

How to use the Inches of Water to PSI

  1. Type the number of inches of water you want to convert.
  2. Read the result in psi straight away — there is no button to press.
  3. Check the table below for the values that come up most often, or reverse the conversion with the linked psi to inches of water page.

Inches of Water to PSI — frequently asked questions

How many psi are in a inches of water?

One inches of water equals 0.0361272905 psi. psi = inH2O × 0.0361272905

What is the formula to convert inches of water to psi?

The formula is psi = inH2O × 0.0361272905. It is an exact definition rather than an approximation, so the conversion never drifts no matter how large the number.

How do I convert psi back to inches of water?

Divide instead of multiplying: one psi is 27.6799058214 inH2O. The reverse converter is linked in the related tools list.

Is this conversion exact?

Yes. Both units are defined against the same base unit by international agreement, so the factor is exact — any rounding you see is only in the display, which you can widen by entering more decimal places.

Is this inches of water to psi free to use?

Yes. Every calculator on the site is free, needs no sign-up, and runs entirely in your browser, so your figures never leave your device.

What people search for

This page answers each of these searches. They are the exact phrases visitors use to find the inches of water to psi.

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About this calculator

Written and reviewed by The Samsung Calculator editorial team. Every calculator is written against a published formula, reviewed against at least one independent reference implementation, and dated when it changes.

Last reviewed August 19, 2026 · Calculation runs client-side · No data collected · Report an error