Convert Kilopascals to Inches of Water
1 kilopascal (kPa) equals 4.01463076 inches of water (inH₂O).
1 kPa = 4.01463076 inH₂O
Type in either box. Scientific notation works: 1.5e-3.
Converting a list? Use the bulk kilopascal to inch of water converter to paste a column from Excel.
How to Convert Kilopascal to Inch of Water
- 1 kPa = 4.01463076 inH₂O
- 1 inH₂O = 0.24908891 kPa
- Example: convert 15 kPa to inH₂O: 15 kPa = 15 × 4.01463076 inH₂O = 60.2194614 inH₂O
Reference conditions. inH₂O: Conventional water column: ρ = 1000 kg/m³ and gₙ = 9.80665 m/s² (≈ water at 4 °C).
Formula
inH₂O = kPa × 4.014630759756
Derivation from SI units:
- 1 kPa = 10³ Pa
- 1 inH₂O = 1000 kg/m³ × 9.80665 m/s² × 0.0254 m = 249.08891 Pa
- 1 kPa = 1000 Pa ÷ 249.08891 Pa per inH₂O = 4.014630759756 inH₂O
Both units are defined exactly, so the factor is exact. Kilopascal definition: kilopascal; Inch of Water definition: inch of water.
Worked examples
- A fan with 1 kPa of static pressure capability is rated 4.01463076 inH₂O.
1 kPa × 4.01463076 = 4.01463076 inH₂O - A 0.5 kPa filter pressure drop is 2.00731538 inH₂O.
0.5 kPa × 4.01463076 = 2.00731538 inH₂O
Kilopascal to Inch of Water conversion table
| Kilopascals (kPa) | Inches of Water (inH₂O) |
|---|---|
| 0.1 kPa | 0.401463076 inH₂O |
| 0.25 kPa | 1.00365769 inH₂O |
| 0.5 kPa | 2.00731538 inH₂O |
| 1 kPa | 4.01463076 inH₂O |
| 2 kPa | 8.02926152 inH₂O |
| 2.5 kPa | 10.0365769 inH₂O |
| 5 kPa | 20.0731538 inH₂O |
| 10 kPa | 40.1463076 inH₂O |
| 20 kPa | 80.2926152 inH₂O |
| 50 kPa | 200.731538 inH₂O |
| 100 kPa | 401.463076 inH₂O |
| 101.325 kPa | 406.7824617 inH₂O |
| 150 kPa | 602.194614 inH₂O |
| 200 kPa | 802.926152 inH₂O |
| 220 kPa | 883.2187671 inH₂O |
| 250 kPa | 1003.65769 inH₂O |
| 300 kPa | 1204.389228 inH₂O |
| 350 kPa | 1405.120766 inH₂O |
| 400 kPa | 1605.852304 inH₂O |
| 500 kPa | 2007.31538 inH₂O |
| 600 kPa | 2408.778456 inH₂O |
| 700 kPa | 2810.241532 inH₂O |
| 800 kPa | 3211.704608 inH₂O |
| 1000 kPa | 4014.63076 inH₂O |
| 2000 kPa | 8029.26152 inH₂O |
Where it's used
Fan curves and duct designs from SI regions in kPa are compared with US equipment rated in inches of water. One kilopascal is roughly 4 inH₂O.
Kilopascal to other pressure units
| Conversion | 1 kPa equals |
|---|---|
| kilopascal to pascal | 1000 Pa |
| kilopascal to megapascal | 0.001 MPa |
| kilopascal to psi | 0.1450377377 psi |
| kilopascal to bar | 0.01 bar |
| kilopascal to millibar | 10 mbar |
| kilopascal to decibar | 0.1 dbar |
| kilopascal to torr | 7.500616827 Torr |
| kilopascal to millimeter of mercury | 7.500615758 mmHg |
| kilopascal to millimeter of water | 101.9716213 mmH₂O |
| kilopascal to centimeter of water | 10.19716213 cmH₂O |
| kilopascal to inch of water | 4.01463076 inH₂O |
| kilopascal to inch of water (60 °F) | 4.01864652 inH₂O (60 °F) |
| kilopascal to inch of mercury | 0.295299833 inHg |
| kilopascal to atmosphere | 0.009869232667 atm |
| kilopascal to barye | 10000 Ba |
Frequently asked questions
How many inches of water is 1 kPa?
1 kPa = 4.01463076 inH₂O (conventional inH₂O).
How many inches of water are in 1 kilopascal?
1 kPa = 4.01463076 inH₂O.
How do I convert kilopascals to inches of water?
Multiply the value in kPa by 4.01463076. For example, 15 kPa × 4.01463076 = 60.2194614 inH₂O.
Is the kPa 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 7, SI prefixes.
- 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 Kilopascals to Inches of Water. Retrieved October 17, 2026, from https://scientificconverters.com/pressure/kilopascal-to-inch-of-water/
IEEE
Scientific Converters, "Convert Kilopascals to Inches of Water," scientificconverters.com. Accessed: Oct. 17, 2026. [Online]. Available: https://scientificconverters.com/pressure/kilopascal-to-inch-of-water/