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.

Altitude to lose (ft)

Altitude to lose before the constraint.

Distance (nm)

Horizontal distance available for the descent.

Compute the descent gradient in feet per nautical mile needed to lose an altitude over a distance. 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]

Gradient (ft/nm)

Required gradient.

• 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.

• Approach Gradient Calculator

  Compute the approach path gradient in percent from altitude lost over nautical miles flown.

• 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.

• Climb Gradient Calculator

  Compute the climb gradient as altitude gained over horizontal distance flown.