Use this calculator for flight-planning study or a first-pass cross-check when all inputs describe the same aircraft, atmospheric condition, and phase of flight.

Elevation (ft)

Airfield elevation above sea level.

QNH (hPa)

Altimeter setting; standard atmosphere when omitted.

Compute pressure altitude from field elevation and the QNH altimeter setting. The tool evaluates the supplied inputs together and returns the named outputs below; it does not infer omitted operating conditions or change the units shown.^[1]

Pressure altitude (ft)

Altitude in the standard atmosphere.

• Do not use a generic calculator in place of the current aircraft flight manual, approved performance data, operating limitations, NOTAMs, weather, or regulations. Real performance changes with configuration, runway condition, altitude, temperature, wind, loading, and technique.
• Use finite inputs in the displayed units and preserve more precision than the final presentation requires. Independently verify safety-critical, financial, compliance, or production decisions.

Cross-check the result against the aircraft flight manual or approved planning system, then apply the required safety margins. Keep signed wind, heading, altitude, speed, and fuel conventions explicit.

• Pressure Altitude From QNH Calculator

  Convert an indicated altitude and QNH into pressure altitude at 27 feet per hectopascal.

• QNH from QFE Field Elevation Calculator

  Approximate QNH from QFE by adding the field elevation pressure at roughly 8.23 meters per hectopascal.

• Field Elevation Pressure Calculator

  Compute the ISA static pressure in hectopascals at a given field elevation.