Enter the sustained wind in knots and the gusting wind in knots into the calculator to determine the gust factor. This calculator can also determine the sustained wind or gust wind if given the other variables.

Gust Factor Formula

The following equation is used to calculate the Gust Factor.

  • Where GF is the fust factor (knots)
  • GWS is the gust wind speed (knots)
  • SWS is the sustained wind speeds (knots)

To calculate the gust factor, subtract the sustained wind speeds from the gusting wind speed.

What is a Gust Factor?


A gust factor is a simple measurement of the difference between sustained wind speeds and gusting wind speeds on a given day.

The gust factor is used by aircraft to adjust for landing parameters on windy days.

How to Calculate a Gust Factor?

Example Problem:

The following example outlines the steps and information needed to calculate the Gust Factor.

First, determine the gusting wind speed. In this example, the winds are gust to 40 knots.

Next, determine the sustained wind speed. In this case, the sustained wind speeds are 25 knots.

Finally, calculate the gust factor using the formula above:


GF = 40 – 25

GF = 15 knots