Bars to Millimeters Of Water (bar to mmH₂O)
1 bar equals 10,197.16213 millimeters of water (rounded).
How to convert bars to millimeters of water
To convert bars to millimeters of water, multiply the number of bars by 10,197.16213. The factor is rounded to 10 significant digits. To go the other way, multiply millimeters of water by 0.0000980665.
millimeters of water = bars × 10,197.16213
Example: 10 bars = 101,971.6213 millimeters of water.
About these units
Bar (bar)
Exactly 100,000 pascals, close to atmospheric pressure at sea level. Used for tire pressure, diving and industrial gauges.
Bar began as a name that meant different things to different people. It comes from the Ancient Greek baros, weight, and from 1793 to 1795 an early metric system used bar for a unit of mass equal to the modern tonne. The pressure bar was introduced by the Norwegian meteorologist Vilhelm Bjerknes, a founder of modern weather forecasting, who defined it as one megadyne per square centimeter. Some earlier writers had used bar for one dyne per square centimeter, a source of confusion.
The bar is a metric unit but not part of the SI, and its official symbol is simply bar, since the old b clashes with the barn and the bit. It has been legally recognized in EU countries since 2004, although NIST deprecates it except for limited use in meteorology.
Its size is handy because 1 bar is slightly less than average sea-level pressure, which is about 1.013 bar. In scuba diving every 10 meters of seawater adds about 1 bar and a full standard tank holds about 200 bar. Tire pressure and turbocharger boost are often quoted in bar outside the US.
1 bar = 100,000 pascals (exactly).
Sources: Wikipedia: Bar (unit); Wikipedia: Atmospheric pressure
Millimeter Of Water (mmH₂O)
Exactly 9.80665 pascals by convention. Used for very low pressures.
A column of water one millimetre tall presses down with 9.80665 Pa under the usual convention, which assumes a density of 1,000 kg/m3 for water at its densest, near 4 degrees Celsius, and standard gravity. NIST marks this conventional millimeter of water as an exact factor. Using the true density of water at 4 degrees Celsius, 999.972 kg/m3, gives about 9.80638 Pa instead, so the two differ in the fifth digit.
Because the unit is so small it suits very low pressures, such as the draft in a duct or a chimney, filter drops and sensitive gauges. It also gives waterproof ratings for fabric, where a tent or jacket rated to some number of millimetres can resist that height of water before leaking. Pressure in this form is often written mmH2O, mmWG or mmWC. Ten millimetres of water is about 98 Pa, or roughly 0.1 percent of one standard atmosphere.
1 millimeter of water = 9.80665 pascals (exactly).
Sources: Wikipedia: Millimetre of water; NIST SP 811, Appendix B.8
Related conversions
- Millimeters of water to bars (reverse)
- Bars to pascals
- Bars to kilopascals
- Bars to standard atmospheres
- Bars to PSI
- Bars to hectopascals
- Bars to megapascals
- Bars to millibars
- Bars to torr
- Bars to millimeters of mercury
- Bars to inches of mercury
- Bars to gigapascals
- Bars to kilopounds per square inch
- Pascals to millimeters of water
- Kilopascals to millimeters of water
- Standard atmospheres to millimeters of water
- PSI to millimeters of water
See all pressure units.