When the engine quits, the single most useful number is how far you can glide. This calculator turns your height above a landing site and the aircraft best glide ratio into a still-air range, a wind-corrected ground range, and the minutes you have before touchdown — the numbers behind a calm engine-failure decision.
How it works
The core formula is simple geometry: in still air, glide range equals height multiplied by the glide ratio. With a 9:1 ratio, every 1,000 ft of height buys 9,000 ft, or about 1.5 nautical miles, of forward travel. The tool converts feet to nautical miles using 6,076.12 ft per nm.
Time aloft comes from your height divided by the best-glide sink rate. The wind correction multiplies the wind component by that time aloft and subtracts it for a headwind or adds it for a tailwind, because wind moves the whole air mass the aircraft is gliding through.
Worked example
At 5,000 ft AGL with a 9:1 glide ratio you have about 7.4 nm of still-air range. Into a 15 kt headwind across roughly 7 minutes of glide, you lose nearly 1.8 nm of ground range — a difference that can decide which field is reachable.
Notes
Real glides fall short of the ideal. Maintain exactly best-glide speed, minimise turns, and always aim to reach your chosen field high so you can spend extra height on the approach rather than stretching the glide.