Inches of Water to Kilopascals
Convert inches of water to kilopascals instantly. 1 inH2O = 0.2490889 kPa. Includes the exact factor, a conversion table of common values and the definition of both units.
How to convert inches of water to kilopascals
To convert inches of water to kilopascals, divide by 4.0146309209 (multiply by 0.2490889). 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.
kPa = inH2O × 0.2490889
Inches of Water to Kilopascals conversion table
The values people look up most often, rounded for reading. Use the calculator above for anything in between.
| Inches of Water | Kilopascals |
|---|---|
| 1 inH2O | 0.249089 kPa |
| 2 inH2O | 0.498178 kPa |
| 3 inH2O | 0.747267 kPa |
| 5 inH2O | 1.245445 kPa |
| 10 inH2O | 2.490889 kPa |
| 20 inH2O | 4.981778 kPa |
| 25 inH2O | 6.227222 kPa |
| 50 inH2O | 12.454445 kPa |
| 100 inH2O | 24.90889 kPa |
| 500 inH2O | 124.54445 kPa |
| 1,000 inH2O | 249.0889 kPa |
What is a inches of water?
A low-pressure unit used for ventilation and gas appliances.
What is a kilopascal?
A thousand pascals. The metric working unit for tyre and system pressures.
The formula
kPa = inH2O × 0.2490889
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 Kilopascals
- Type the number of inches of water you want to convert.
- Read the result in kilopascals 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 kilopascals to inches of water page.
Inches of Water to Kilopascals — frequently asked questions
How many kilopascals are in a inches of water?
One inches of water equals 0.2490889 kPa. kPa = inH2O × 0.2490889
What is the formula to convert inches of water to kilopascals?
The formula is kPa = inH2O × 0.2490889. It is an exact definition rather than an approximation, so the conversion never drifts no matter how large the number.
How do I convert kilopascals back to inches of water?
Divide instead of multiplying: one kilopascal is 4.0146309209 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 kilopascals 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 kilopascals.
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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