Inches of Water to Pascals
Convert inches of water to pascals instantly. 1 inH2O = 249.0889 Pa. Includes the exact factor, a conversion table of common values and the definition of both units.
How to convert inches of water to pascals
To convert inches of water to pascals, multiply by 249.0889. 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.
Pa = inH2O × 249.0889
Inches of Water to Pascals conversion table
The values people look up most often, rounded for reading. Use the calculator above for anything in between.
| Inches of Water | Pascals |
|---|---|
| 1 inH2O | 249.0889 Pa |
| 2 inH2O | 498.1778 Pa |
| 3 inH2O | 747.2667 Pa |
| 5 inH2O | 1,245.44 Pa |
| 10 inH2O | 2,490.89 Pa |
| 20 inH2O | 4,981.78 Pa |
| 25 inH2O | 6,227.22 Pa |
| 50 inH2O | 12,454.44 Pa |
| 100 inH2O | 24,908.89 Pa |
| 500 inH2O | 124,544.45 Pa |
| 1,000 inH2O | 249,088.9 Pa |
What is a inches of water?
A low-pressure unit used for ventilation and gas appliances.
What is a pascal?
The SI unit of pressure: one newton per square metre.
The formula
Pa = inH2O × 249.0889
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 Pascals
- Type the number of inches of water you want to convert.
- Read the result in pascals straight away — there is no button to press.
- Check the table below for the values that come up most often, or reverse the conversion with the linked pascals to inches of water page.
Inches of Water to Pascals — frequently asked questions
How many pascals are in a inches of water?
One inches of water equals 249.0889 Pa. Pa = inH2O × 249.0889
What is the formula to convert inches of water to pascals?
The formula is Pa = inH2O × 249.0889. It is an exact definition rather than an approximation, so the conversion never drifts no matter how large the number.
How do I convert pascals back to inches of water?
Divide instead of multiplying: one pascal is 0.0040146309 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 pascals 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
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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