Pressure

Inches of Water to Megapascals

Convert inches of water to megapascals instantly. 1 inH2O = 0.0002490889 MPa. Includes the exact factor, a conversion table of common values and the definition of both units.

inH2O
Megapascals
—
One step, one exact factorInches of Waterwhat you have× 0.0002490889Megapascalswhat 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 megapascals

To convert inches of water to megapascals, divide by 4014.6309209282 (multiply by 0.0002490889). 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.

MPa = inH2O × 0.0002490889

Inches of Water to Megapascals conversion table

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

Inches of WaterMegapascals
1 inH2O0.0002491 MPa
2 inH2O0.0004982 MPa
3 inH2O0.0007473 MPa
5 inH2O0.001245 MPa
10 inH2O0.002491 MPa
20 inH2O0.004982 MPa
25 inH2O0.006227 MPa
50 inH2O0.012454 MPa
100 inH2O0.024909 MPa
500 inH2O0.124544 MPa
1,000 inH2O0.249089 MPa

What is a inches of water?

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

What is a megapascal?

A million pascals, used for material strength and hydraulics.

The formula

MPa = inH2O × 0.0002490889

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 Megapascals

  1. Type the number of inches of water you want to convert.
  2. Read the result in megapascals 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 megapascals to inches of water page.

Inches of Water to Megapascals — frequently asked questions

How many megapascals are in a inches of water?

One inches of water equals 0.0002490889 MPa. MPa = inH2O × 0.0002490889

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

The formula is MPa = inH2O × 0.0002490889. It is an exact definition rather than an approximation, so the conversion never drifts no matter how large the number.

How do I convert megapascals back to inches of water?

Divide instead of multiplying: one megapascal is 4014.6309209282 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 megapascals 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 megapascals.

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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