Convert Inch of water to Pascal
1 inch of water = 249.0889 pascal (Pa). For example, 10 inch of water = 2,490.889 pascal and 100 inch of water = 24,908.89 pascal. Type any value below to convert inch of water to pascal both ways — it runs entirely in your browser.
Quick answer: Inch of water to Pascal
1 Inch of water = 249.0889 Pascal (inH₂O → Pa). To convert inch of water to pascal, multiply by 249.0889. To convert pascal to inch of water, multiply by 0.004014631. The converter at the top does this instantly and both ways; the sections below give the formula, worked examples, a full conversion chart and answers to the most common inch of water-to-pascal questions.
How to convert Inch of water to Pascal
To convert inch of water to pascal, multiply the number of inch of water by the conversion factor 249.0889, because 1 inH₂O = 249.0889 Pa. The conversion is linear, so the same factor works for any value — whole numbers, decimals or fractions. For the reverse direction, 1 Pa = 0.004014631 inH₂O, so you divide by 249.0889 (or multiply by 0.004014631) to turn pascal back into inch of water.
Pa = inH₂O × 249.0889 ·
inH₂O = Pa × 0.004014631
- Write down the value you want to convert, in inch of water.
- Multiply it by 249.0889.
- The result is the same area/length/quantity expressed in pascal.
Inch of water to Pascal — worked examples
Each row shows the exact arithmetic so you can follow the conversion step by step. For example, 5 inch of water is 1,245.445 pascal because 5 inH₂O × 249.0889 = 1,245.445 Pa.
| Inch of water | Calculation | Pascal |
|---|---|---|
| 1 inH₂O | 1 inH₂O × 249.0889 = 249.0889 Pa | 249.0889 Pa |
| 2 inH₂O | 2 inH₂O × 249.0889 = 498.1778 Pa | 498.1778 Pa |
| 3 inH₂O | 3 inH₂O × 249.0889 = 747.2667 Pa | 747.2667 Pa |
| 5 inH₂O | 5 inH₂O × 249.0889 = 1,245.445 Pa | 1,245.445 Pa |
| 7 inH₂O | 7 inH₂O × 249.0889 = 1,743.622 Pa | 1,743.622 Pa |
| 10 inH₂O | 10 inH₂O × 249.0889 = 2,490.889 Pa | 2,490.889 Pa |
| 12 inH₂O | 12 inH₂O × 249.0889 = 2,989.067 Pa | 2,989.067 Pa |
| 15 inH₂O | 15 inH₂O × 249.0889 = 3,736.334 Pa | 3,736.334 Pa |
| 20 inH₂O | 20 inH₂O × 249.0889 = 4,981.778 Pa | 4,981.778 Pa |
| 25 inH₂O | 25 inH₂O × 249.0889 = 6,227.223 Pa | 6,227.223 Pa |
| 50 inH₂O | 50 inH₂O × 249.0889 = 12,454.45 Pa | 12,454.45 Pa |
| 100 inH₂O | 100 inH₂O × 249.0889 = 24,908.89 Pa | 24,908.89 Pa |
Common Inch of water to Pascal conversions
These are the inch of water-to-pascal values people look up most often. Every figure is computed from the exact factor, so you can rely on them for quick reference:
- 1 inch of water = 249.0889 pascal
- 2 inch of water = 498.1778 pascal
- 2.5 inch of water = 622.7223 pascal
- 3 inch of water = 747.2667 pascal
- 4 inch of water = 996.3556 pascal
- 5 inch of water = 1,245.445 pascal
- 6 inch of water = 1,494.533 pascal
- 7 inch of water = 1,743.622 pascal
- 8 inch of water = 1,992.711 pascal
- 9 inch of water = 2,241.8 pascal
- 10 inch of water = 2,490.889 pascal
- 12 inch of water = 2,989.067 pascal
- 15 inch of water = 3,736.334 pascal
- 20 inch of water = 4,981.778 pascal
- 25 inch of water = 6,227.223 pascal
- 30 inch of water = 7,472.667 pascal
- 50 inch of water = 12,454.45 pascal
- 75 inch of water = 18,681.67 pascal
- 100 inch of water = 24,908.89 pascal
- 200 inch of water = 49,817.78 pascal
- 500 inch of water = 124,544.5 pascal
- 1000 inch of water = 249,088.9 pascal
Inch of water to Pascal conversion chart (both directions)
The chart below converts inch of water to pascal and pascal to inch of water side by side, so it works whichever way you need. 1 inch of water = 249.0889 pascal, and 1 pascal = 0.004014631 inch of water.
| Inch of water → Pascal | Pascal → Inch of water |
|---|---|
| 0.25 inH₂O = 62.27223 Pa | 0.25 Pa = 0.001003658 inH₂O |
| 0.5 inH₂O = 124.5445 Pa | 0.5 Pa = 0.002007315 inH₂O |
| 1 inH₂O = 249.0889 Pa | 1 Pa = 0.004014631 inH₂O |
| 2 inH₂O = 498.1778 Pa | 2 Pa = 0.008029262 inH₂O |
| 3 inH₂O = 747.2667 Pa | 3 Pa = 0.01204389 inH₂O |
| 4 inH₂O = 996.3556 Pa | 4 Pa = 0.01605852 inH₂O |
| 5 inH₂O = 1,245.445 Pa | 5 Pa = 0.02007315 inH₂O |
| 6 inH₂O = 1,494.533 Pa | 6 Pa = 0.02408778 inH₂O |
| 7 inH₂O = 1,743.622 Pa | 7 Pa = 0.02810242 inH₂O |
| 8 inH₂O = 1,992.711 Pa | 8 Pa = 0.03211705 inH₂O |
| 9 inH₂O = 2,241.8 Pa | 9 Pa = 0.03613168 inH₂O |
| 10 inH₂O = 2,490.889 Pa | 10 Pa = 0.04014631 inH₂O |
| 12 inH₂O = 2,989.067 Pa | 12 Pa = 0.04817557 inH₂O |
| 15 inH₂O = 3,736.334 Pa | 15 Pa = 0.06021946 inH₂O |
| 20 inH₂O = 4,981.778 Pa | 20 Pa = 0.08029262 inH₂O |
| 25 inH₂O = 6,227.223 Pa | 25 Pa = 0.1003658 inH₂O |
| 30 inH₂O = 7,472.667 Pa | 30 Pa = 0.1204389 inH₂O |
| 40 inH₂O = 9,963.556 Pa | 40 Pa = 0.1605852 inH₂O |
| 50 inH₂O = 12,454.45 Pa | 50 Pa = 0.2007315 inH₂O |
| 75 inH₂O = 18,681.67 Pa | 75 Pa = 0.3010973 inH₂O |
| 100 inH₂O = 24,908.89 Pa | 100 Pa = 0.4014631 inH₂O |
| 150 inH₂O = 37,363.34 Pa | 150 Pa = 0.6021946 inH₂O |
| 200 inH₂O = 49,817.78 Pa | 200 Pa = 0.8029262 inH₂O |
| 250 inH₂O = 62,272.23 Pa | 250 Pa = 1.003658 inH₂O |
| 500 inH₂O = 124,544.5 Pa | 500 Pa = 2.007315 inH₂O |
| 1000 inH₂O = 249,088.9 Pa | 1000 Pa = 4.014631 inH₂O |
Inch of water vs Pascal: which is bigger?
A inch of water is the larger unit: one inch of water equals 249.0889 pascals. Put another way, you need 249.0889 pascals to make a single inch of water.
What is a Inch of water? History, origin and usage
The inch of water is the imperial counterpart of the millimetre of water, and it became entrenched in North American heating and ventilation practice, where it is usually written "inches WC" for water column. Gas utilities adopted it because household gas supply pressures are small enough that a water manometer reads them comfortably.
Inches of water are used for duct pressure and fan static pressure in heating and air-conditioning, for natural-gas appliance supply pressure, and for cleanroom and filter differential pressures.
Residential natural gas is typically delivered at around 7 inches of water column — a pressure so low that it would barely register on a tyre gauge. An inch of water is exactly 25.4 millimetres of water.
What is a Pascal? History, origin and usage
The pascal is named after Blaise Pascal, who in 1648 had his brother-in-law carry a mercury barometer up the Puy de Dôme in central France and watch the mercury column fall as he climbed. That experiment showed air has weight and that the pressure it exerts drops with height. The unit itself is much younger: the name was adopted by the General Conference on Weights and Measures in 1971, replacing the older habit of writing pressures as "newtons per square metre".
The pascal is the SI unit of pressure and the base every other unit on this page is defined against. On its own it is awkwardly small for daily life — a sheet of paper resting on a table presses down with only a few pascals — so real-world figures are almost always given with a prefix: hectopascals for weather, kilopascals for tyres and gas, megapascals for concrete and hydraulics.
One pascal is one newton spread over one square metre, which is about the pressure of a five-rupee coin lying flat on a table. Because pressure is force divided by area, the same push concentrated into a smaller area gives a much higher pressure — which is why a drawing pin goes into a wall and your thumb does not.
Convert 1 Inch of water to other units
It can help to see a inch of water next to the other units it is commonly compared with. One inch of water (inH₂O) is equal to:
| 1 Inch of water equals | Unit |
|---|---|
| 249.0889 Pa | Pascal |
| 2.490889 hPa | Hectopascal |
| 0.2490889 kPa | Kilopascal |
| 0.0002490889 MPa | Megapascal |
| 2.490889 mbar | Millibar |
| 0.002490889 bar | Bar |
| 0.002458316 atm | Standard atmosphere |
| 1.86832 Torr | Torr |
| 1.86832 mmHg | Millimetre of mercury |
| 0.07355591 inHg | Inch of mercury |
| 25.4 mmH₂O | Millimetre of water |
| 0.03612729 psi | Pound per square inch |
| 0.00254 kgf/cm² | Kilogram-force per square centimetre |
Convert 1 Pascal to other units
One pascal (Pa) is equal to:
| 1 Pascal equals | Unit |
|---|---|
| 0.01 hPa | Hectopascal |
| 0.001 kPa | Kilopascal |
| 0.000001 MPa | Megapascal |
| 0.01 mbar | Millibar |
| 0.00001 bar | Bar |
| 0.000009869233 atm | Standard atmosphere |
| 0.007500617 Torr | Torr |
| 0.007500616 mmHg | Millimetre of mercury |
| 0.0002952998 inHg | Inch of mercury |
| 0.1019716 mmH₂O | Millimetre of water |
| 0.004014631 inH₂O | Inch of water |
| 0.0001450377 psi | Pound per square inch |
| 0.00001019716 kgf/cm² | Kilogram-force per square centimetre |
Tips for converting Inch of water to Pascal
- To go from inch of water to pascal, multiply by 249.0889; to go back, divide by 249.0889 (or multiply by 0.004014631).
- For a quick mental estimate, remember that 1 inch of water ≈ 249.0889 pascal, so 10 inch of water ≈ 2,490.889 pascal.
- The converter above keeps full precision; the tables round for readability, so use the tool for exact figures.
- Both fields update live as you type — change either side to convert in that direction.
How to use this Inch of water to Pascal converter
Type a number into the Inch of water field and the equivalent in Pascal appears instantly — there is no “convert” button to press and nothing is sent to a server, so it works offline once the page has loaded and is safe for any data. You can also type into the Pascal field to convert the other way (pascal to inch of water). Use the swap control to flip the two units, and copy the result with a single click. Because the calculation runs in your browser with full floating-point precision, the converter is more exact than the rounded figures shown in the reference chart above — use the chart for quick look-ups and the tool for precise work.
Accuracy and method
Every figure on this page — the formula, the worked examples, the conversion chart and the “convert to other units” tables — is computed from a single verified conversion factor (1 inH₂O = 249.0889 Pa), never copied from a hand-typed lookup table that could drift. That factor is derived from each unit’s definition in terms of a common base unit, and an automated check re-verifies all of the site’s factors on every update, so the numbers here stay correct over time. This matters for inch of water-to-pascal conversions because a small rounding error in a published table compounds quickly at larger quantities; computing from the exact factor avoids that.
Sources
- NIST Special Publication 811 — Guide for the Use of the SI — publishes the exact metric equivalents of the customary pressure units. A psi is one pound of force over one square inch, and the 1959 international yard-and-pound agreement fixes the pound at exactly 0.453 592 37 kilogram and the inch at exactly 0.0254 metre, while standard gravity is fixed at exactly 9.806 65 m/s² — so psi, inches of mercury and inches of water are defined exactly rather than measured.
- BIPM — The International System of Units (SI Brochure) — the defining document for the SI, published by the International Bureau of Weights and Measures. It fixes the base unit that this conversion resolves to, which is why the factor here can be exact rather than approximate.
Pressure factors here come from fixed definitions, anchored to the pascal: a bar is exactly 100,000 Pa, one atmosphere is exactly 101,325 Pa, a torr is exactly a 760th of an atmosphere, and psi is built from the exact pound and the exact inch. Two of them — psi and the torr — work out to decimals that repeat forever, so where a number is shown rounded it is marked, not quietly trimmed.
Frequently asked questions
- How many pascal are in 1 inch of water?
- 1 inch of water = 249.0889 pascal (Pa). To convert any number of inch of water to pascal, multiply by 249.0889.
- How do I convert inch of water to pascal?
- Multiply the number of inch of water by 249.0889. For example, 10 inch of water = 10 × 249.0889 = 2,490.889 pascal, and 25 inch of water = 6,227.223 pascal.
- How many inch of water are in 1 pascal?
- 1 pascal = 0.004014631 inch of water. So to convert pascal back to inch of water, multiply by 0.004014631.
- What is the formula to convert inch of water to pascal?
- pascal = inch of water × 249.0889. The reverse formula is inch of water = pascal × 0.004014631.
- How much is 100 inch of water in pascal?
- 100 inch of water = 24,908.89 pascal. (And 1000 inch of water = 249,088.9 pascal.)
- Which is bigger, a inch of water or a pascal?
- A inch of water is larger: 1 inch of water = 249.0889 pascal.
- Is this inch of water to pascal converter accurate?
- Yes — every value is computed from the exact 249.0889 Pa per inH₂O factor (not rounded look-up tables), and the factors are re-verified automatically on every update.
- Can I convert pascal to inch of water too?
- Yes. The converter works both ways — enter a value in either field. 1 pascal = 0.004014631 inch of water.