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.

TAS (kt)

True airspeed.

Altitude (ft)

Altitude where the TAS applies.

Factor per 1000 ft

TAS gain per thousand feet of altitude.

Convert true airspeed back to calibrated airspeed using the two-percent-per-thousand-feet rule. 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]

CAS (kt)

Calibrated airspeed.

• 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.

• True Airspeed Calculator

  Estimate true airspeed from calibrated airspeed using the two-percent-per-thousand-feet rule.

• Rate of Climb from Gradient Calculator

  Compute the climb rate in feet per minute required to sustain a climb gradient at a given true airspeed.

• Cabin Rate of Climb

  Calculate the average cabin-altitude change in feet per minute from two cabin altitudes and elapsed minutes. A negative result means cabin descent; this is a measured average, not an aircraft operating limit.