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.

Horizontal distance (ft)

Horizontal distance from the departure point to the obstacle.

Obstacle height (ft)

Height of the obstacle above the departure point.

Compute the climb gradient required to clear an obstacle over a given horizontal 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]

Required gradient (%)

Climb gradient required to clear the obstacle.

• 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.

• Climb Gradient Calculator

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

• 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.

• Required Descent Gradient Calculator

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