Glide Distance Calculator

How it works

Still-air distance = height AGL × glide ratio ÷ 6,076. Wind is applied by scaling for the change in groundspeed at best glide speed.

Best glide is flown indicated, but sink rate and groundspeed are true-airspeed quantities, so the speed you enter is converted to TAS at the mid-height of the descent on a standard day before either is worked out. That is why the descent rate here is higher, and the time to the ground shorter, than dividing height by an indicated-speed sink rate would suggest. The glide distance is unaffected — height × L/D is a geometric ratio.

Read this number skeptically

It assumes you are already at best glide speed, the propeller is stopped or feathered, the aircraft is clean, you are turning nothing, and the ground below is level. Every one of those is optimistic in a real engine failure. A windmilling propeller alone can cost a substantial fraction of the glide ratio.

It also assumes you start gliding immediately. The seconds spent recognizing the failure and lowering the nose are paid for in height, and they are the most expensive seconds of the flight.

Use it for planning, not for stretching

The right use is on the ground: deciding what altitude keeps a landable field within reach on a given route. The wrong use is in the air, trying to reach a field the number says is just barely attainable.