Density Altitude Calculator
Estimate pressure and density altitude (ft)
How to Use This Calculator
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
Frequently Asked 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.