Plain English Meaning
To find out how long a leg of a flight will take, divide the distance you need to cover by your speed across the ground. Faster groundspeed means less time; longer distance means more time.
Full Definition
A flight planning formula used to calculate the time required to fly a given distance, where Time (T) equals Distance (D) divided by Groundspeed (GS). Distance is expressed in nautical miles and groundspeed in knots, producing a result in hours that is typically converted to minutes for practical use.
Context Anchor
Used in cross-country flight planning, navigation logs, and fuel planning when estimating how long each leg of a flight will take.
Derivation
The formula comes from the basic speed relationship: speed equals distance divided by time. Rearranging that relationship to solve for time gives time equals distance divided by speed. In aviation planning, the speed used here is groundspeed because the ’s movement the ground determines when it will arrive.