Density Altitude Calculator

Work out density altitude instantly with clear inputs, formula shown and shareable results.

About Density Altitude Calculator

Density altitude is the pressure altitude corrected for temperature: the altitude at which the standard atmosphere has the same air density as the air you are actually in. The standard approximation adds about 118.8 ft per degree Celsius above the ISA temperature, with a small extra allowance for high humidity, which lowers density further.

Formula

Density altitude

DA = PA + 118.8 x (OAT - ISA temp), ISA temp = 15 - 1.98 x PA/1000

Worked example

With the default values below, Density Altitude Calculator returns Density altitude of 5,648. Change any input above and every figure here is recalculated in your browser.

Inputs used

Pressure altitude: 3,000 ft
Outside air temperature: 30 °C
Dew point: 18 °C

Results

Density altitude: 5,648 ft
ISA temperature at this altitude: 9.10 °C
ISA deviation: 20.90 °C
Density ratio (sigma): 0.8519

Step by step

1Values used
2Density altitude
3Density altitude= 5,648 ft
4ISA temperature at this altitude= 9.10 °C
5ISA deviation= 20.90 °C
6Density ratio (sigma)= 0.8519

Assumptions and limits

The result is derived only from the 3 inputs listed above. Anything not among them is not part of the calculation.
In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
Figures are rounded for display to 4 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
Aviation results are planning estimates only. Always verify take-off, landing, fuel, weight and balance figures against the certified Aircraft Flight Manual, current performance charts and applicable aviation regulations before flight.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Aviation results are planning estimates only. Always verify take-off, landing, fuel, weight and balance figures against the certified Aircraft Flight Manual, current performance charts and applicable aviation regulations before flight.

Frequently Asked Questions

Why does high density altitude matter?

Engine power, propeller thrust and lift all fall with air density, so take-off runs lengthen, climb gradients flatten and true airspeed for a given indicated airspeed rises.

Does humidity really change density altitude?

Yes, but only slightly. Water vapour is lighter than dry air, so a very humid day adds a few hundred feet at most, which is why it is applied as a small correction.