Pilot Tool

Pressure Altitude Calculator

Enter your field elevation and altimeter setting — in inHg or hPa — and get pressure altitude instantly. The formula and worked examples are below.

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Type an identifier or tap Nearby to fill the calculator from the latest official observation. U.S. stations (NWS).
Airport elevation above mean sea level, in feet.
From ATIS/ASOS/AWOS. Standard = 29.92 inHg.
Pressure Altitude
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Enter elevation and altimeter setting

Pressure altitude is your field elevation corrected for non-standard pressure: the altitude your altimeter reads with 29.92 inHg (1013.25 hPa) set. It's the starting point for density altitude and the number most POH performance charts are built around. This tool uses the standard aviation formula and updates the moment you type — no button to press.

The pressure altitude formula

The calculator above uses the formula every pilot learns:

Pressure Altitude = Field Elevation + (29.92 − Altimeter Setting) × 1,000

The altimeter setting is in inches of mercury. If your setting is below 29.92, the term is positive and pressure altitude sits above field elevation; if it's above 29.92, pressure altitude drops below field elevation. Working in hPa? Convert first with inHg = hPa × 0.02953 (so 1013.25 hPa = 29.92 inHg), then apply the same formula — the calculator does this conversion for you when you switch the unit toggle.

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Worked example

A field at 5,000 ft with an altimeter setting of 29.42 inHg (a low-pressure day):

PA = 5,000 + (29.92 − 29.42) × 1,000 = 5,000 + 500 = 5,500 ft

The half-inch of low pressure adds 500 ft: the airplane's altimeter and performance behave as if the field were 500 ft higher than it is. Switch the tool to hPa and enter 996 hPa for the same field — you'll get the same answer, because 996 hPa is essentially 29.42 inHg.

Why pressure altitude matters

On its own, pressure altitude rarely decides a flight — but it's the mandatory first step to the number that does: density altitude. Density altitude takes pressure altitude and corrects it for temperature, giving the altitude the airplane actually performs at. Get pressure altitude wrong and every downstream performance figure is wrong too. It's also the reference for flight levels, altimetry above the transition altitude, and most takeoff and landing charts in your POH. In short: pressure altitude is the clean, temperature-free baseline, and density altitude is what you plan the takeoff around.

Next step — add temperature for Density Altitude

To understand how these two numbers relate, read Pressure Altitude vs Density Altitude. For the full density-altitude method with examples, see How to Calculate Density Altitude, and for what high numbers do to your runway, how density altitude affects takeoff and climb.

Frequently asked questions

What is the pressure altitude formula?
Pressure altitude = field elevation + (29.92 − altimeter setting in inHg) × 1,000. If the setting is in hPa, convert first: inHg = hPa × 0.02953. A lower setting than 29.92 gives a pressure altitude above field elevation; a higher setting gives one below.
How do I find pressure altitude without a calculator?
Set 29.92 inHg (1013 hPa) in your altimeter's Kollsman window and read the altitude it shows — that's pressure altitude. Away from the airplane, use the formula: each 0.01 inHg below 29.92 adds about 10 ft, or each 1 hPa below 1013 adds about 30 ft.
Is pressure altitude the same as field elevation?
Only when the altimeter setting is exactly 29.92 inHg (1013.25 hPa). At any other setting, pressure altitude differs from field elevation — lower pressure raises it, higher pressure lowers it.
What's the difference between pressure altitude and density altitude?
Pressure altitude corrects field elevation for non-standard pressure only. Density altitude then corrects pressure altitude for non-standard temperature and humidity. Density altitude is the number that reflects actual aircraft performance.
Do I use inHg or hPa for pressure altitude?
Either — they describe the same pressure. US altimeter settings use inches of mercury (inHg, standard 29.92); most of the world uses hectopascals (hPa, standard 1013.25). This calculator accepts both and converts internally.
Why is my pressure altitude higher than the airport elevation?
Because the altimeter setting is below 29.92 inHg — a low-pressure day. The formula adds (29.92 − setting) × 1,000 ft, so a setting of 29.42 on a 1,000 ft field gives a pressure altitude of about 1,500 ft.
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