Altimeter Setting Converter

Convert between inHg and hPa/mb pressure settings

The Altimeter Setting Converter precisely translates atmospheric pressure readings, critical for aircraft altimeter calibration, between different units. Users provide a Pressure Value and specify its From Unit (inHg or hPa/mb). The tool then returns the equivalent pressure setting in Inches of Mercury and Hectopascals. This is essential for pilots, air traffic controllers, and dispatchers who operate globally, as pressure reports vary by region (e.g., North America uses inHg, Europe uses hPa). The converter ensures accurate altimeter settings for safe flight operations, bridging unit differences. The Inches of Mercury and Hectopascals outputs are direct unit conversions of the initial Pressure Value. The ISA Deviation output is particularly significant, showing the difference between the given pressure and the International Standard Atmosphere sea-level pressure (29.92 inHg or 1013.25 hPa). A positive ISA Deviation indicates local pressure is higher than standard, implying denser air. A negative deviation signifies lower pressure and less dense air. This helps aviators interpret current atmospheric conditions relative to a standard day for flight planning and performance.

Inputs

Provide the following 2 values to run the Altimeter Setting Converter:

Pressure Value [number] (required)
From Unit [select] (required)

What it calculates

This tool returns:

Inches of Mercury (inHg) — primary result
Hectopascals (hPa)
ISA Deviation (hPa)

Worked example

For the sample inputs below:

Pressure Value: 1000
From Unit: inHg

the Altimeter Setting Converter produces:

Inches of Mercury: 1000 inHg
Hectopascals: 33864 hPa
ISA Deviation: 32850.7 hPa

Frequently Asked Questions

What is an altimeter setting?

An altimeter setting is the pressure value used to adjust an altimeter for atmospheric conditions, ensuring accurate altitude readings.

How do I use the Altimeter Setting Converter?

Just enter the pressure value in either inHg or hPa/mb, and click convert to see the equivalent value in the other unit.

Why is it important to convert altimeter settings?

Converting altimeter settings is crucial for pilots and navigators to ensure they maintain the correct altitude relative to sea level and avoid collisions.

What is the difference between inHg and hPa/mb?

InHg (inches of mercury) and hPa/mb (hectopascal/millibar) are units of pressure; inHg is commonly used in the US, while hPa/mb is more common in aviation globally.

Is the Altimeter Setting Converter free to use?

Yes, the Altimeter Setting Converter is completely free to use and accessible to anyone needing quick and easy conversions.