Convert Pascals to Inches of Water
1 pascal (Pa) equals 0.00401463076 inches of water (inH₂O).
1 Pa = 0.00401463076 inH₂O
Type in either box. Scientific notation works: 1.5e-3.
Converting a list? Use the bulk pascal to inch of water converter to paste a column from Excel.
How to Convert Pascal to Inch of Water
- 1 Pa = 0.00401463076 inH₂O
- 1 inH₂O = 249.08891 Pa
- Example: convert 15 Pa to inH₂O: 15 Pa = 15 × 0.00401463076 inH₂O = 0.0602194614 inH₂O
Reference conditions. inH₂O: Conventional water column: ρ = 1000 kg/m³ and gₙ = 9.80665 m/s² (≈ water at 4 °C).
Formula
inH₂O = Pa × 0.004014630759756
or inH₂O = Pa ÷ 249.08891
Derivation from SI units:
- 1 Pa = 1 N/m² = 1 kg·m⁻¹·s⁻²
- 1 inH₂O = 1000 kg/m³ × 9.80665 m/s² × 0.0254 m = 249.08891 Pa
Both units are defined exactly, so the factor is exact. Pascal definition: pascal; Inch of Water definition: inch of water.
Worked examples
- A cleanroom held 25 Pa above the corridor shows 0.100365769 inH₂O on a US differential gauge.
25 Pa × 0.00401463076 = 0.100365769 inH₂O - 125 Pa, the ASTM D737 test pressure, equals 0.501828845 inH₂O, the familiar "half inch of water".
125 Pa × 0.00401463076 = 0.501828845 inH₂O
Pascal to Inch of Water conversion table
| Pascals (Pa) | Inches of Water (inH₂O) |
|---|---|
| 1 Pa | 0.00401463076 inH₂O |
| 5 Pa | 0.0200731538 inH₂O |
| 10 Pa | 0.0401463076 inH₂O |
| 15 Pa | 0.0602194614 inH₂O |
| 25 Pa | 0.100365769 inH₂O |
| 50 Pa | 0.200731538 inH₂O |
| 75 Pa | 0.301097307 inH₂O |
| 100 Pa | 0.401463076 inH₂O |
| 125 Pa | 0.501828845 inH₂O |
| 150 Pa | 0.602194614 inH₂O |
| 200 Pa | 0.802926152 inH₂O |
| 250 Pa | 1.00365769 inH₂O |
| 300 Pa | 1.204389228 inH₂O |
| 400 Pa | 1.605852304 inH₂O |
| 500 Pa | 2.00731538 inH₂O |
| 750 Pa | 3.01097307 inH₂O |
| 1000 Pa | 4.01463076 inH₂O |
| 1500 Pa | 6.02194614 inH₂O |
| 2000 Pa | 8.02926152 inH₂O |
| 2500 Pa | 10.0365769 inH₂O |
| 5000 Pa | 20.0731538 inH₂O |
| 10000 Pa | 40.1463076 inH₂O |
| 50000 Pa | 200.731538 inH₂O |
| 101325 Pa | 406.7824617 inH₂O |
Where it's used
Filter pressure drop, fan static pressure and room pressurisation are measured in pascals in SI documents and in inches of water (in WC) on US equipment. The conversion comes up constantly when matching European filter data to US HVAC controls and gauges.
Pascal to other pressure units
| Conversion | 1 Pa equals |
|---|---|
| pascal to kilopascal | 0.001 kPa |
| pascal to megapascal | 0.000001 MPa |
| pascal to psi | 0.0001450377377 psi |
| pascal to bar | 0.00001 bar |
| pascal to millibar | 0.01 mbar |
| pascal to decibar | 0.0001 dbar |
| pascal to torr | 0.007500616827 Torr |
| pascal to millimeter of mercury | 0.007500615758 mmHg |
| pascal to millimeter of water | 0.1019716213 mmH₂O |
| pascal to centimeter of water | 0.01019716213 cmH₂O |
| pascal to inch of water | 0.00401463076 inH₂O |
| pascal to inch of water (60 °F) | 0.00401864652 inH₂O (60 °F) |
| pascal to inch of mercury | 0.000295299833 inHg |
| pascal to atmosphere | 0.000009869232667 atm |
| pascal to barye | 10 Ba |
Frequently asked questions
Which inch of water does this converter use?
The conventional inch of water (1000 kg/m³ water, standard gravity), exactly 249.08891 Pa. Some US references use water at 60 °F (248.84 Pa), about 0.1 % smaller; that unit has its own converter.
How many inches of water are in 1 pascal?
1 Pa = 0.00401463076 inH₂O.
How do I convert pascals to inches of water?
Multiply the value in Pa by 0.00401463076, or divide it by 249.08891. For example, 15 Pa × 0.00401463076 = 0.0602194614 inH₂O.
Is the Pa to inH₂O conversion exact?
Yes. Both units are defined exactly, so the ratio is exact; its decimal form does not terminate and is shown here to 10 significant figures (more with the precision selector).
Sources
- The International System of Units (SI), 9th edition (SI Brochure), Bureau International des Poids et Mesures , Table 4, coherent derived units with special names.
- Guide for the Use of the International System of Units (SI), NIST Special Publication 811, 2008 Edition, National Institute of Standards and Technology , Appendix B.8, "inch of water, conventional (inH2O)".
Last reviewed: . Factors are stored exactly and computed with 50-digit decimal arithmetic. See how we verify conversion factors.
Cite this page
APA
Scientific Converters. (2026, October 15). Convert Pascals to Inches of Water. Retrieved October 17, 2026, from https://scientificconverters.com/pressure/pascal-to-inch-of-water/
IEEE
Scientific Converters, "Convert Pascals to Inches of Water," scientificconverters.com. Accessed: Oct. 17, 2026. [Online]. Available: https://scientificconverters.com/pressure/pascal-to-inch-of-water/