Convert Millibars to Inches of Water
1 millibar (mbar) equals 0.401463076 inches of water (inH₂O).
1 mbar = 0.401463076 inH₂O
Type in either box. Scientific notation works: 1.5e-3.
Converting a list? Use the bulk millibar to inch of water converter to paste a column from Excel.
How to Convert Millibar to Inch of Water
- 1 mbar = 0.401463076 inH₂O
- 1 inH₂O = 2.4908891 mbar
- Example: convert 15 mbar to inH₂O: 15 mbar = 15 × 0.401463076 inH₂O = 6.02194614 inH₂O
Reference conditions. inH₂O: Conventional water column: ρ = 1000 kg/m³ and gₙ = 9.80665 m/s² (≈ water at 4 °C).
Formula
inH₂O = mbar × 0.4014630759756
or inH₂O = mbar ÷ 2.4908891
Derivation from SI units:
- 1 mbar = 10⁻³ bar = 100 Pa = 1 hPa
- 1 inH₂O = 1000 kg/m³ × 9.80665 m/s² × 0.0254 m = 249.08891 Pa
- 1 mbar = 100 Pa ÷ 249.08891 Pa per inH₂O = 0.4014630759756 inH₂O
Both units are defined exactly, so the factor is exact. Millibar definition: millibar; Inch of Water definition: inch of water.
Worked examples
- The UK natural-gas supply pressure of 20 mbar is 8.02926152 inH₂O.
20 mbar × 0.401463076 = 8.02926152 inH₂O - A propane supply pressure of 37 mbar is 14.85413381 inH₂O.
37 mbar × 0.401463076 = 14.85413381 inH₂O
Millibar to Inch of Water conversion table
| Millibars (mbar) | Inches of Water (inH₂O) |
|---|---|
| 0.1 mbar | 0.0401463076 inH₂O |
| 0.5 mbar | 0.200731538 inH₂O |
| 1 mbar | 0.401463076 inH₂O |
| 2 mbar | 0.802926152 inH₂O |
| 5 mbar | 2.00731538 inH₂O |
| 10 mbar | 4.01463076 inH₂O |
| 20 mbar | 8.02926152 inH₂O |
| 25 mbar | 10.0365769 inH₂O |
| 37 mbar | 14.85413381 inH₂O |
| 50 mbar | 20.0731538 inH₂O |
| 100 mbar | 40.1463076 inH₂O |
| 250 mbar | 100.365769 inH₂O |
| 500 mbar | 200.731538 inH₂O |
| 900 mbar | 361.3167684 inH₂O |
| 950 mbar | 381.3899222 inH₂O |
| 980 mbar | 393.4338145 inH₂O |
| 1000 mbar | 401.463076 inH₂O |
| 1013.25 mbar | 406.7824617 inH₂O |
| 1020 mbar | 409.4923375 inH₂O |
| 1050 mbar | 421.5362298 inH₂O |
Where it's used
European gas pressures in mbar are converted to inches of water when using US regulators, manometers or appliance documentation.
Millibar to other pressure units
| Conversion | 1 mbar equals |
|---|---|
| millibar to pascal | 100 Pa |
| millibar to kilopascal | 0.1 kPa |
| millibar to megapascal | 0.0001 MPa |
| millibar to psi | 0.01450377377 psi |
| millibar to bar | 0.001 bar |
| millibar to decibar | 0.01 dbar |
| millibar to torr | 0.7500616827 Torr |
| millibar to millimeter of mercury | 0.7500615758 mmHg |
| millibar to millimeter of water | 10.19716213 mmH₂O |
| millibar to centimeter of water | 1.019716213 cmH₂O |
| millibar to inch of water | 0.401463076 inH₂O |
| millibar to inch of water (60 °F) | 0.401864652 inH₂O (60 °F) |
| millibar to inch of mercury | 0.0295299833 inHg |
| millibar to atmosphere | 0.0009869232667 atm |
| millibar to barye | 1000 Ba |
Frequently asked questions
How many inches of water is 1 mbar?
1 mbar = 0.401463076 inH₂O.
How many inches of water are in 1 millibar?
1 mbar = 0.401463076 inH₂O.
How do I convert millibars to inches of water?
Multiply the value in mbar by 0.401463076, or divide it by 2.4908891. For example, 15 mbar × 0.401463076 = 6.02194614 inH₂O.
Is the mbar 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
- 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, "millibar".
- 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 Millibars to Inches of Water. Retrieved October 17, 2026, from https://scientificconverters.com/pressure/millibar-to-inch-of-water/
IEEE
Scientific Converters, "Convert Millibars to Inches of Water," scientificconverters.com. Accessed: Oct. 17, 2026. [Online]. Available: https://scientificconverters.com/pressure/millibar-to-inch-of-water/