Barometric Pressure Conversion

What is Barometric Pressure Conversion?

A Barometric Pressure Conversion is the process of translating the measurement of atmospheric pressure from one unit to another. Barometric pressure, also known as atmospheric pressure, is the force exerted by the weight of the air in the atmosphere. It is a key indicator in meteorology for forecasting weather.

Common units for barometric pressure include:

• Inches of Mercury (inHg): Traditionally used in the United States and in aviation worldwide.
• Millibars (mbar): A metric unit, where 1 bar = 1000 mbar. It is nearly identical to the hectoPascal (hPa) and is used by meteorologists globally.
• Standard Atmosphere (atm): A reference unit equal to the average sea-level pressure.
• Pounds per Square Inch (PSI): The standard imperial unit for pressure.

Our Barometric Pressure Conversion calculator allows for seamless switching between these and other units, which is essential for pilots, sailors, and weather enthusiasts.

How to Use the Barometric Pressure Converter

Our converter is a comprehensive tool that provides both direct conversions and a full table of equivalent values.

1. Enter a Value: Type the pressure reading you want to convert into the "Value" field.
2. Select the 'From' Unit: Choose your starting unit from the first dropdown menu (e.g., 'Inch of mercury').
3. Select the 'To' Unit: Choose your target unit from the second dropdown (e.g., 'Millibar').
4. View the Direct Result: The calculator instantly shows the converted value.
5. Consult the Full Table: For a complete picture, a table below the main converter shows your input value converted to all common pressure units at once.

The Conversion Formulas

All conversions are based on internationally agreed-upon standards, with the Pascal (Pa) as the base SI unit. The key relationships are:

$$ 1 \text{ atm} = 29.9213 \text{ inHg} = 1013.25 \text{ mbar} = 101325 \text{ Pa} = 14.6959 \text{ PSI} $$

For example, to convert from inHg to mbar, the formula is:

$$ \text{mbar} = \text{inHg} \times \frac{1013.25}{29.9213} \approx \text{inHg} \times 33.8639 $$

Practical Example: Aviation

A pilot in the United States receives an altimeter setting (QNH) from air traffic control of 29.92 inHg. This is the standard pressure setting. Later, the pilot is flying in a region where the pressure is given in millibars. They receive a new setting of 1013 mbar. The pilot wants to confirm this is essentially the same standard pressure.

• Known Value: 29.92 inHg
• Using the calculator: Entering "29.92" in the value field and selecting "inHg" as the 'from' unit, the quick-reference table would immediately show the value in other units.
• Result: The table would show approximately 1013.2 mbar, confirming that the new setting is standard pressure.

This conversion is critical for flight safety, as it ensures the aircraft's altimeter is calibrated correctly. For other pressure conversions, you can use our Bar to Atm Converter or the general Pressure Converter. For force calculations, check out our Force Converter.

Why is Barometric Pressure Important?

• Weather Forecasting: Falling pressure generally indicates approaching storms and unstable weather, while rising pressure suggests calm and clear conditions.
• Aviation: Pilots must constantly adjust their altimeters to the local barometric pressure to ensure they are flying at the correct altitude.
• Outdoor Activities: Hikers and mountaineers use barometric pressure to gauge altitude and anticipate weather changes.

To get real-time weather and barometric pressure data, you can visit the National Weather Service website. For information on aviation standards, the Federal Aviation Administration (FAA) is an authoritative resource.