What this calculator shows
A wind triangle combines the aircraft's motion through the air with wind to find the resulting motion over the ground. This calculator solves for the true heading needed to maintain a true course and reports the resulting ground speed.
The wind direction is entered as the direction it is coming from. Course and wind direction must both use true north. Convert magnetic references before using them together.
How to use the calculator
Enter the desired true course, true airspeed, wind direction from true north, and wind speed in knots. The calculator updates immediately and stores the inputs in the URL.
Use a true airspeed appropriate to the flight condition. Wind observations and forecasts can differ from the conditions along the route, so this mathematical solution does not establish what the aircraft will encounter.
How the calculation works
The wind vector is resolved into components along and across the desired course. The aircraft is then turned into the crosswind so that its lateral airspeed cancels the cross-track wind:
wind correction angle = arcsine(-crosswind / true airspeed)
true heading = true course + wind correction angle
ground speed = true airspeed x cosine(wind correction angle) + along-track wind
If the crosswind component is greater than true airspeed, no heading can maintain the desired course. The calculator reports that no solution exists rather than showing an invalid result.
Example calculation
For a true course of 360 deg, true airspeed of 100 kt, and wind from 270 deg at 20 kt, the wind blows from the left across the course.
The computed wind correction is about 11.5 deg left. The required true heading is about 348.5 deg, and the resulting ground speed is about 98 kt.
Assumptions and limitations
This is a two-dimensional steady-wind calculation. It assumes the aircraft can maintain the entered true airspeed and does not account for turns, climb, descent, wind variation, turbulence, magnetic variation, or navigation-system errors.
The result is a planning aid. Verify headings, wind references, aircraft performance, and route conditions using current official sources and the applicable POH or AFM.
Sources and methodology
The vector method is the standard wind-triangle relationship used in navigation. The FAA Pilot's Handbook of Aeronautical Knowledge covers navigation and wind effects. True airspeed, wind, and direction inputs must be based on appropriate aircraft and weather information.
Related tools and resources
Flight planning
About this site
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