The Glide Ratio calculator computes the glide ratio based on the change in forward distance and the change in altitude.
INSTRUCTION: Choose units and enter the following:
Glide Ratio (ε): The calculator returns the Glide Ratio as a real number.
The Glide Ratio is the ratio of distance forward to distance downwards when a glider is flown at a constant speed in still air. The glide ratio varies with air speed, but there is a maximum value which is frequently quoted. Glide ratio usually varies little with vehicle load; a heavier vehicle glides faster, but nearly maintains its glide ratio.
The following formula is used:
ε = ΔS / ΔH
where:
Wikipedia (https://en.wikipedia.org/wiki/Gliding_flight#Glide_ratio)