Inches of mercury (inHg) | hectopascals (hPa) |
---|---|
0 | 0 |
1 | 33.863889532611 |
2 | 67.727779065222 |
3 | 101.59166859783 |
4 | 135.45555813044 |
5 | 169.31944766305 |
6 | 203.18333719567 |
7 | 237.04722672828 |
8 | 270.91111626089 |
9 | 304.7750057935 |
10 | 338.63889532611 |
20 | 677.27779065222 |
30 | 1015.9166859783 |
40 | 1354.5555813044 |
50 | 1693.1944766305 |
60 | 2031.8333719567 |
70 | 2370.4722672828 |
80 | 2709.1111626089 |
90 | 3047.750057935 |
100 | 3386.3889532611 |
1000 | 33863.889532611 |
Converting between inches of mercury (inHg) and hectopascals (hPa) involves understanding the relationship between these two units of pressure. Here's a breakdown of the conversion process, some relevant context, and examples.
Inches of mercury (inHg) is commonly used in the United States to measure atmospheric pressure, particularly in aviation and meteorology. Hectopascals (hPa) are the standard unit of pressure in the International System of Units (SI) and are widely used in meteorology worldwide. One hectopascal is equal to one millibar (mbar).
These conversion factors are derived from the definition of these units based on standard gravity and temperature ().
To convert from inches of mercury to hectopascals, multiply the value in inches of mercury by the conversion factor 33.86389.
Formula:
Example: Convert 1 inch of mercury to hectopascals
To convert from hectopascals to inches of mercury, multiply the value in hectopascals by the conversion factor 0.02953.
Formula:
Example: Convert 1 hectopascal to inches of mercury
The inch of mercury as a unit is historically linked to the mercury barometer, invented by Evangelista Torricelli in the 17th century. Torricelli, an Italian physicist and mathematician, was the first to create a sustained vacuum and is credited with inventing the barometer. The height of the mercury column in the barometer directly corresponds to the atmospheric pressure. The standard atmosphere (1 atm) is defined as 29.9213 inches of mercury or 1013.25 hPa. NIST - Pressure Units
Here are some common pressure values converted between inches of mercury and hectopascals:
These conversions are useful in various applications, from weather forecasting to aviation, ensuring accurate readings and interpretations across different measurement systems.
See below section for step by step unit conversion with formulas and explanations. Please refer to the table below for a list of all the hectopascals to other unit conversions.
The "inches of mercury" (inHg) is a unit of pressure commonly used in the United States. It's based on the height of a column of mercury that the given pressure will support. This unit is frequently used in aviation, meteorology, and vacuum applications.
Inches of mercury is a manometric unit of pressure. It represents the pressure exerted by a one-inch column of mercury at a standard temperature (usually 0°C or 32°F) under standard gravity.
The basic principle is that atmospheric pressure can support a certain height of a mercury column in a barometer. Higher atmospheric pressure corresponds to a higher mercury column, and vice versa. Therefore, the height of this column, measured in inches, serves as a direct indication of the pressure.
Here's how inches of mercury relates to other pressure units:
The concept of measuring pressure using a column of liquid is closely linked to Evangelista Torricelli, an Italian physicist and mathematician. In 1643, Torricelli invented the mercury barometer, demonstrating that atmospheric pressure could support a column of mercury. His experiments led to the understanding of vacuum and the quantification of atmospheric pressure. Britannica - Evangelista Torricelli has a good intro about him.
Aviation: Aircraft altimeters use inches of mercury to indicate altitude. Pilots set their altimeters to a local pressure reading (inHg) to ensure accurate altitude readings. Standard sea level pressure is 29.92 inHg.
Meteorology: Weather reports often include atmospheric pressure readings in inches of mercury. These readings are used to track weather patterns and predict changes in weather conditions. For example, a rising barometer (increasing inHg) often indicates improving weather, while a falling barometer suggests worsening weather.
Vacuum Systems: In various industrial and scientific applications, inches of mercury is used to measure vacuum levels. For example, vacuum pumps might be rated by the amount of vacuum they can create, expressed in inches of mercury. Higher vacuum levels (i.e., more negative readings) are crucial in processes like freeze-drying and semiconductor manufacturing. For example, common home vacuum cleaners operate in a range of 50 to 80 inHg.
Medical Equipment: Some medical devices, such as sphygmomanometers (blood pressure monitors), historically used mmHg (millimeters of mercury), a related unit. While digital devices are common now, the underlying principle remains tied to pressure measurement.
Standard Atmospheric Pressure: Standard atmospheric pressure at sea level is approximately 29.92 inches of mercury (inHg). This value is often used as a reference point for various measurements and calculations.
Altitude Dependence: Atmospheric pressure decreases with altitude. As you ascend, the weight of the air above you decreases, resulting in lower pressure readings in inches of mercury.
Temperature Effects: While "inches of mercury" typically refers to a standardized temperature, variations in temperature can slightly affect the density of mercury and, consequently, the pressure reading.
Hectopascals (hPa) are a commonly used unit of pressure, particularly in meteorology. The following sections will detail what they are, how they relate to other units, and their real-world applications.
A hectopascal (hPa) is a unit of pressure defined as 100 pascals (Pa). The pascal itself is the SI unit of pressure, defined as one newton per square meter (). Therefore, 1 hPa is equivalent to 100 .
The prefix "hecto" signifies a factor of 100. This makes the hectopascal a convenient unit for measuring atmospheric pressure, as it avoids the use of excessively large or small numbers. It's directly related to other units, most notably the millibar (mbar).
This equivalence is why you'll often see hPa and mbar used interchangeably in weather reports. The older unit of pressure, the atmosphere (atm), is approximately 1013.25 hPa at sea level under standard conditions.
Hectopascals are the standard unit for reporting atmospheric pressure in meteorology. Weather maps and forecasts routinely use hPa to depict high and low-pressure systems. These pressure systems drive weather patterns. For example, low-pressure systems are often associated with clouds and precipitation, while high-pressure systems are typically associated with clear skies.
Convert 1 inHg to other units | Result |
---|---|
Inches of mercury to pascals (inHg to Pa) | 3386.3889532611 |
Inches of mercury to kilopascals (inHg to kPa) | 3.3863889532611 |
Inches of mercury to megapascals (inHg to MPa) | 0.003386388953261 |
Inches of mercury to hectopascals (inHg to hPa) | 33.863889532611 |
Inches of mercury to millibar (inHg to mbar) | 33.863889532611 |
Inches of mercury to bar (inHg to bar) | 0.03386388953261 |
Inches of mercury to torr (inHg to torr) | 25.400005965738 |
Inches of mercury to meters of water @ 4°C (inHg to mH2O) | 0.345315571909 |
Inches of mercury to millimeters of mercury (inHg to mmHg) | 25.400076155931 |
Inches of mercury to pounds per square inch (inHg to psi) | 0.491154 |
Inches of mercury to kilopound per square inch (inHg to ksi) | 0.000491154 |