Convert Pascals to Millimeters of Water
1 pascal (Pa) equals 0.1019716213 millimeters of water (mmH₂O).
1 Pa = 0.1019716213 mmH₂O
Type in either box. Scientific notation works: 1.5e-3.
Converting a list? Use the bulk pascal to millimeter of water converter to paste a column from Excel.
How to Convert Pascal to Millimeter of Water
- 1 Pa = 0.1019716213 mmH₂O
- 1 mmH₂O = 9.80665 Pa
- Example: convert 15 Pa to mmH₂O: 15 Pa = 15 × 0.1019716213 mmH₂O = 1.529574319 mmH₂O
Reference conditions. mmH₂O: Conventional water column: ρ = 1000 kg/m³ and gₙ = 9.80665 m/s² (≈ water at 4 °C).
Formula
mmH₂O = Pa × 0.1019716212978
or mmH₂O = Pa ÷ 9.80665
Derivation from SI units:
- 1 Pa = 1 N/m² = 1 kg·m⁻¹·s⁻²
- 1 mmH₂O = 1000 kg/m³ × 9.80665 m/s² × 0.001 m = 9.80665 Pa
Both units are defined exactly, so the factor is exact. Pascal definition: pascal; Millimeter of Water definition: millimeter of water.
Worked examples
- A cooling coil with a 100 Pa air-side pressure drop shows 10.19716213 mmH₂O on an Asian datasheet.
100 Pa × 0.1019716213 = 10.19716213 mmH₂O - By definition 9.80665 Pa is exactly 1 mmH₂O.
9.80665 Pa × 0.1019716213 = 1 mmH₂O
Pascal to Millimeter of Water conversion table
| Pascals (Pa) | Millimeters of Water (mmH₂O) |
|---|---|
| 1 Pa | 0.1019716213 mmH₂O |
| 5 Pa | 0.5098581065 mmH₂O |
| 10 Pa | 1.019716213 mmH₂O |
| 15 Pa | 1.529574319 mmH₂O |
| 25 Pa | 2.549290532 mmH₂O |
| 50 Pa | 5.098581065 mmH₂O |
| 75 Pa | 7.647871597 mmH₂O |
| 100 Pa | 10.19716213 mmH₂O |
| 125 Pa | 12.74645266 mmH₂O |
| 150 Pa | 15.29574319 mmH₂O |
| 200 Pa | 20.39432426 mmH₂O |
| 250 Pa | 25.49290532 mmH₂O |
| 300 Pa | 30.59148639 mmH₂O |
| 400 Pa | 40.78864852 mmH₂O |
| 500 Pa | 50.98581065 mmH₂O |
| 750 Pa | 76.47871597 mmH₂O |
| 1000 Pa | 101.9716213 mmH₂O |
| 1500 Pa | 152.9574319 mmH₂O |
| 2000 Pa | 203.9432426 mmH₂O |
| 2500 Pa | 254.9290532 mmH₂O |
| 5000 Pa | 509.8581065 mmH₂O |
| 10000 Pa | 1019.716213 mmH₂O |
| 50000 Pa | 5098.581065 mmH₂O |
| 101325 Pa | 10332.27453 mmH₂O |
Where it's used
Fans, filters and dampers made in Japan, Korea, China and parts of Europe are often rated in mmH₂O (mmAq). Converting pascals to mmH₂O lets you compare them with SI data; roughly 10 Pa make one millimetre of water.
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
Is 1 mmH₂O exactly 10 Pa?
No. The conventional millimetre of water is exactly 9.80665 Pa. Using 10 Pa as a rule of thumb introduces an error of about 2 %.
How many millimeters of water are in 1 pascal?
1 Pa = 0.1019716213 mmH₂O.
How do I convert pascals to millimeters of water?
Multiply the value in Pa by 0.1019716213, or divide it by 9.80665. For example, 15 Pa × 0.1019716213 = 1.529574319 mmH₂O.
Is the Pa to mmH₂O 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, "millimeter of water, conventional (mmH2O)".
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 Millimeters of Water. Retrieved October 17, 2026, from https://scientificconverters.com/pressure/pascal-to-millimeter-of-water/
IEEE
Scientific Converters, "Convert Pascals to Millimeters of Water," scientificconverters.com. Accessed: Oct. 17, 2026. [Online]. Available: https://scientificconverters.com/pressure/pascal-to-millimeter-of-water/