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Aviation calculators/Altitude calculations
ALTITUDE CALCULATIONS

Altitude calculations

See how pressure and temperature change the altitude your aircraft experiences.

Instant resultsQNH, QNE & QFE explainedBuilt for pilots & student pilots

Airfield & weather

Live calculation

Use the published airfield elevation, current QNH, and outside air temperature at the airfield.

ft MSL
−1,500 to 20,000 ft
hPa
Sea-level altimeter setting
°C
Temperature at the airfield
Pressure units

Your altitude picture.

LIVE RESULTS
Pressure altitude5,500 ft

Altimeter set to QNE / standard pressure

Density altitude8,008 ft

Temperature-adjusted planning estimate

ISA temperature at pressure altitude 4.1 °COAT versus ISA +20.9 °C
THREE ALTIMETER REFERENCES

Where QNH, QNE & QFE sit.

At the airfield, each setting gives the altimeter a different zero reference and reading.

How it works
AIRFIELD5,500 ft MSLMEAN SEA LEVEL · QNHSTANDARD PRESSURE DATUM · QNEQFE reads 0 at field
Illustrative reference positions; vertical distances are not to scale. QNE is the standard altimeter setting, not a measured layer of air.
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

Two altitudes, two questions.

Pressure altitude

Pressure altitude is what a correctly functioning altimeter indicates when set to standard pressure, 1013.25 hPa (29.92 inHg). We estimate airfield pressure from QNH and airfield elevation using the standard atmosphere, then find the corresponding pressure altitude.

Density altitude

Density altitude describes air density as an equivalent altitude in the standard atmosphere. This calculator uses the common planning approximation: pressure altitude plus 120 ft for each °C that the outside temperature is above the standard temperature at that pressure altitude.

Planning approximationDensity altitude ≈ pressure altitude + 120 × (OAT − ISA temperature) ft
ALTIMETER SETTINGS

What each setting means.

QNH makes the altimeter read the airfield elevation above mean sea level while on the airfield.

QNE means the standard setting, 1013.25 hPa / 29.92 inHg. The indication is pressure altitude, used as the common flight-level reference where applicable.

QFE is local pressure at the airfield reference datum; when set, the altimeter reads approximately zero at that datum. Its indicated height is relative to the airfield, not mean sea level.

Definitions and method: FAA Pilot’s Handbook of Aeronautical Knowledge · FAA aeronautical contractions · FAA density altitude approximation

A planning aid. Use published data for flight.

QFE is estimated from QNH using a standard-atmosphere altimeter model. Density altitude is approximate and does not account for humidity. Verify the current altimeter setting and use approved aircraft performance charts and local procedures before flight.