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Performance
Gradient / Angle Converter Calculator
Convert flight-path angle to ft/NM gradient and percent grade, or convert an entered gradient back to an angle.
deg
ft/NM
Gradient from angle—
Angle from gradient—
Percent grade—
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A 3° path in ft/NM
A 3° path gives tan(3°) × 6,076.1 ≈ 318 ft/NM and tan(3°) × 100 ≈ 5.24%.
The angle and gradient inputs are converted independently. A 3° path is not a 3% grade, and 318 ft/NM does not mean 318 fpm.
Formula and method
Flight-path gradient and angle are connected by tangent geometry; percent grade and feet per nautical mile are different ways to express the same slope.