Density Altitude Calculator
Estimate pressure and density altitude (ft)
Instructions
Enter Field Elevation
Altitude of the runway or location above mean sea level.
Enter Altimeter Setting
Sea-level pressure in inches of mercury from ATIS/METAR.
Enter Temperature
Outside air temperature in °C.
Calculate
Review pressure and density altitude results.
Formula
PA = Elev + (29.92 − Alt) · 1000
T_ISA(°C) ≈ 15 − 1.98 · (PA/1000)
DA ≈ PA + 120 · (OAT − T_ISA)
Where: Elev = field elevation (ft), Alt = altimeter (inHg)
Example: Elev=5000 ft, Alt=30.12 inHg, OAT=30°C → PA≈4680 ft, DA≈7440 ft
About Density Altitude
Density altitude reflects air density in terms of an equivalent standard atmosphere altitude. Higher DA reduces engine power, prop/wing efficiency, and climb performance.
- Hot, high, and humid conditions increase density altitude
- Plan longer takeoff rolls and reduced climb rates at high DA
Common Questions
Does humidity affect density altitude?
Yes, humid air is less dense; this simplified method approximates the impact via temperature deviation.
Should I use station pressure instead?
This method uses altimeter setting per common pilot practice; station pressure methods also exist.