Crosswind and headwind calculator
Enter the runway and the wind to see the headwind (or tailwind) and crosswind components for both ends of the runway, for steady wind and gusts.
Runs entirely in your browser
| Runway end | Wind | Headwind or tailwind | Crosswind |
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Simple trigonometry on the wind you enter. Not for flight planning or navigation: use the aircraft's demonstrated crosswind limit and the official wind report, and remember that runway numbers and tower winds are magnetic while METAR winds are true.
How to find the crosswind component
- Enter the runway number (such as 27 or 09L) or its heading in degrees (such as 275).
- Enter the direction the wind is coming from, its speed and, if reported, the gust speed. Pick the speed unit.
- Read the headwind or tailwind and the crosswind for each end of the runway. Check which end gives a headwind.
The formula
Let θ be the angle from the runway heading to the direction the wind is blowing from, and V the wind speed. The component along the runway is headwind = V · cos θ (negative means tailwind) and the component across it is crosswind = V · sin θ, positive from the right and negative from the left. This is the standard wind-triangle decomposition used in pilot training, for example in the FAA Pilot's Handbook of Aeronautical Knowledge (FAA-H-8083-25, chapter on aircraft performance) and the Airplane Flying Handbook (FAA-H-8083-3).
The opposite runway end has a heading 180 degrees away, so its headwind is the negative of the first and its crosswind switches side. The runway number is the magnetic heading in tens of degrees rounded to the nearest ten. Speeds are converted exactly (1 knot = 1.852 km/h, 1 mph = 1.609344 km/h, 1 m/s = 3.6 km/h).
The calculation ignores wind shear, gust fronts and terrain effects, and uses a single wind value. Not for flight planning or navigation.
Questions
How is the crosswind calculated?
Take the angle between the wind direction and the runway heading. The crosswind is the wind speed times the sine of that angle, and the headwind is the wind speed times its cosine. A wind 30 degrees off the runway at 20 knots gives a 10-knot crosswind and about a 17-knot headwind.
Should I use the gust speed?
Yes, pilots usually check both. The gust column shows the components for the peak gust, which is the worst case you may meet in the flare or the rollout.
What do the left and right mean?
Right means the wind is blowing from the right-hand side when you face along the runway in the direction of landing or take-off. Left means from the left. A negative headwind is a tailwind.
Does the runway number mean degrees?
A runway number is the magnetic heading divided by ten and rounded: runway 27 points to about 270 degrees, runway 09 to about 090. The opposite end is 180 degrees away (09 and 27, or 36 and 18). Entering a three-digit number uses it as an exact heading.
Are the wind and the runway in the same reference?
They should be. Tower and ATIS winds are given in degrees magnetic, while METAR and TAF winds are in degrees true. The difference is the local magnetic variation, which can be a few degrees or more than ten. Use the same reference for both inputs.
What is a safe crosswind?
It depends on the aircraft, the runway and the pilot. The aircraft manual lists a maximum demonstrated crosswind, which is not a legal limit but is a good guide. This calculator does not give limits.