Altitude Pressure Calculator
Calculate atmospheric pressure changes with altitude and elevation for aviation, mountaineering, and weather applications. Essential for pilots, hikers, and meteorologists needing precise pressure calculations at different elevations.
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Complete Guide: Altitude Pressure Calculator
Everything you need to know about using this tool effectively
Enter an altitude and temperature to calculate the atmospheric pressure at that elevation. Results display in hectopascals (hPa), millimeters of mercury (mmHg), and atmospheres (atm). The calculator uses the barometric formula to model how pressure decreases with altitude in the troposphere.
The calculator applies the barometric formula P = P0 * exp(-g * M * h / (R * T)), where P0 is sea level pressure (1013.25 hPa), g is gravitational acceleration, M is molar mass of air, h is altitude, R is the gas constant, and T is temperature in Kelvin. This exponential relationship shows pressure dropping roughly 1 hPa per 8.5 meters near sea level.
Aviation planning
Pilots can estimate pressure at cruising altitude for altimeter calibration and flight planning.
Mountaineering
Hikers and climbers can predict oxygen availability and pressure conditions at high elevations.
Weather analysis
Meteorologists can cross-reference altitude-based pressure with observed readings for forecasting.
Engineering design
Engineers can determine pressure conditions for HVAC systems, combustion engines, or sealed enclosures at elevation.
Enter the altitude
Type the elevation in meters or feet for which you want the pressure.
Set the temperature
Enter the ambient air temperature at that altitude for a more accurate result.
Read the pressure values
The calculator shows the pressure in hPa, mmHg, and atm simultaneously.
Use standard temperature (15 degrees C at sea level) for approximate results when actual temperature is unknown
Remember that pressure drops faster at higher altitudes due to the exponential relationship
For aviation use, cross-check with local METAR reports for the most accurate readings
The calculator models the troposphere; results become less accurate above 11,000 meters
What formula does this calculator use?
It uses the barometric formula P = P0 * exp(-gMh/RT), which models the exponential decrease of atmospheric pressure with altitude under standard gravity and constant temperature.
Why does temperature matter for the calculation?
Air density and pressure distribution change with temperature. Warmer air is less dense, so pressure decreases more slowly with altitude compared to colder air. Including temperature gives a more accurate result.
How accurate is this calculator?
The calculator is accurate to within a few percent for altitudes below 11,000 meters in the troposphere. Above that, the assumption of constant temperature breaks down and results become approximate.
Can I use this for diving or underwater pressure?
No, this calculator models atmospheric pressure in air. Underwater pressure involves a different calculation that adds the weight of the water column above the diver.
What is the standard sea level pressure used?
The calculator uses 1013.25 hPa (29.92 inHg) as the standard sea level pressure, which is the internationally agreed standard atmosphere value.