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To convert from hectopascal (hPa) to meter of water @ 4°C (mH2O), use the following formula:
Let's convert 5 hectopascal (hPa) to meter of water @ 4°C (mH2O).
Using the formula:
Therefore, 5 hectopascal (hPa) is equal to meter of water @ 4°C (mH2O).
Here are some quick reference conversions from hectopascal (hPa) to meter of water @ 4°C (mH2O):
| hectopascals | meters of water @ 4°C |
|---|---|
| 0.000001 hPa | mH2O |
| 0.001 hPa | mH2O |
| 0.1 hPa | mH2O |
| 1 hPa | mH2O |
| 2 hPa | mH2O |
| 3 hPa | mH2O |
| 4 hPa | mH2O |
| 5 hPa | mH2O |
| 6 hPa | mH2O |
| 7 hPa | mH2O |
| 8 hPa | mH2O |
| 9 hPa | mH2O |
| 10 hPa | mH2O |
| 20 hPa | mH2O |
| 30 hPa | mH2O |
| 40 hPa | mH2O |
| 50 hPa | mH2O |
| 100 hPa | mH2O |
| 1000 hPa | mH2O |
| 10000 hPa | mH2O |
For all Pressure converters, choose units using the From/To dropdowns above.
A hectopascal (hPa) is a metric unit used to measure pressure.
You will most commonly see it in weather reports to describe atmospheric pressure (also known as barometric pressure).
If you've seen millibars (mbar) on older weather maps, the hectopascal is its modern replacement.
The switch was simple for meteorologists because the units are exactly the same (1 hPa = 1 mbar).
The hectopascal is now the international standard for measuring atmospheric pressure, making weather data consistent worldwide.
The conversion is in the name. The prefix "hecto-" means 100. This makes the math simple:
Just as "hecto-" means 100, "kilo-" means 1,000. This defines their relationship:
A meter of water @ 4°C (mH2O) is a metric unit used to measure pressure.
It is precisely defined as 9.80665 kilopascals (kPa).
The specific temperature of 4°C (39.2°F) is key because this is the point where pure water is at its heaviest or most dense (approximately 999.972 kg/m3).
Using this temperature provides a stable and reliable standard for defining pressure.
This precision is essential in scientific and engineering fields like hydraulics and fluid mechanics, ensuring that measurements of pressure head are consistent and accurate across different applications and locations.
The unit "meter of water" (mH2O) is frequently used in civil engineering, hydrology, and irrigation to measure water levels and pressure.
It provides an intuitive way to express the pressure exerted by a column of water, such as the water level in a reservoir, dam, or groundwater well. This measurement is sometimes referred to as the 'piezometric head'.
It is also commonly used to specify the performance of pumps, indicating the height to which a pump can lift water.
For practical use, it's often helpful to know how mH2O converts to other common pressure units.
One mH2O is equal to:
These conversion factors allow engineers and scientists to easily translate pressure specifications between different international and imperial systems.