Density Altitude Calculator
Density altitude from field elevation, altimeter setting and outside air temperature (dry air).
Atmosphere and Altitude
Atmosphere and Altitude
The International Standard Atmosphere and the altitudes built on it: pressure altitude, density altitude, air density, the speed of sound and altimeter setting conversions. Start here to see why thin, warm air changes so many other numbers.
Calculators
Pressure Altitude Calculator
Pressure altitude from elevation and the current altimeter setting.
Atmosphere and Altitude
Standard Atmosphere Calculator
ISA temperature, pressure, density and speed of sound at any altitude up to 20 km.
Atmosphere and Altitude
Air Density Calculator
Air density from pressure, temperature and optional relative humidity.
Atmosphere and Altitude
Speed of Sound Calculator
Speed of sound in air from temperature, in knots, m/s, km/h, mph and ft/s.
Atmosphere and Altitude
Altimeter Pressure Conversion Calculator
Convert altimeter settings between inHg, hPa (millibars), mmHg, kPa and psi.
Atmosphere and Altitude
Guides
Atmosphere and Altitude
Aviation Altimeter Settings Explained
How an altimeter setting works, what QNH and the standard setting show, how inHg and hPa convert, and what a wrong setting does to indicated altitude.
Atmosphere and Altitude
Understanding the Speed of Sound
The speed of sound in air depends on temperature, not pressure or density. See the formula, a table of values and how it sets Mach number.
Atmosphere and Altitude
Air Density and Aircraft Performance
Pressure, temperature and humidity set air density, and density sets how much lift, thrust and power an aircraft can produce. Here is how they connect.
Atmosphere and Altitude
International Standard Atmosphere Explained
The ISA model fixes sea-level values, a 6.5 °C per km lapse rate and an 11 km tropopause. See the equations, a reference table and what ISA deviation means.
Atmosphere and Altitude
Understanding Pressure Altitude
Pressure altitude is altitude measured from the 1013.25 hPa (29.92 inHg) standard datum. Learn how to read it, calculate it and where it is used.
Atmosphere and Altitude
What Is Density Altitude?
Density altitude is pressure altitude corrected for non-standard temperature. See the exact formula, the 120 ft per °C shortcut and a worked example.