Warm high airfield
At 5,500 ft, QNH 1013.25 hPa and 25 °C, pressure altitude is 5,500 ft and estimated density altitude is 8,008 ft.
ALTITUDE CALCULATIONS
Density altitude calculator
Estimate how pressure and temperature combine to affect the air your aircraft flies in.
Airfield & weather
Live calculationUse the published airfield elevation, current QNH, and outside air temperature at the airfield.
ft MSL
Use −1,500 to 20,000 ft.hPa
Use 800–1,100 hPa.°C
Use −80 to 60 °C.Pressure units
Density altitude
LIVE RESULTTemperature-adjusted estimate8,008 ft
Air density expressed as a standard-atmosphere altitude
Pressure altitude 5,500 ftISA temperature at pressure altitude 4.1 °COAT versus ISA +20.9 °C
THREE ALTIMETER REFERENCES
How it works QNH, QNE & QFE at a glance.
QNH is referenced to mean sea level, QFE to the airfield. The dotted QNE datum moves relative to QNH as the pressure setting changes.
Swipe diagram to see all three settings →
QNH1013.25 hPa
Reads 5,500 ft MSL at the airfield.
QNE1013.25 hPa
Reads 5,500 ft pressure altitude at the airfield.
QFE827.42 hPa
Reads approximately 0 ft at the airfield reference datum.
THE METHOD
From pressure to density.
We first calculate pressure altitude from airfield elevation and QNH. Then we compare outside air temperature with standard ISA temperature at that pressure altitude. Warmer-than-standard air raises density altitude; colder-than-standard air lowers it.
Planning approximation
Density altitude ≈ pressure altitude + 120 × (OAT − ISA temperature) ftEnter QNH in hPa or inHg and temperature in °C. Pressure values display to two decimal places and altitude to the nearest foot; calculations retain full precision. This dry-air estimate excludes humidity.
WORKED EXAMPLES01 02
Density altitude in practice.
Standard sea level
At 0 ft, QNH 1013.25 hPa and 15 °C, both pressure altitude and estimated density altitude are approximately 0 ft.
Density altitude questions
What makes density altitude increase?+
Higher temperature and lower pressure reduce air density and generally raise density altitude.
Does this calculator include humidity?+
No. It uses the common dry-air planning approximation, so humid conditions can make actual density lower than this estimate suggests.
Can I use density altitude as takeoff performance data?+
No. Use the approved aircraft handbook and current conditions for takeoff, climb and landing performance.
A planning aid. Use approved performance data.
Density altitude is approximate. Check current weather and calculate takeoff, climb and landing performance with your aircraft’s approved handbook.