Crosswind Calculator | Calculate Wind Components

Crosswind Calculator

Split a reported wind into the component acting across a runway and the component acting along it. Enter wind speed and the smallest angle between the wind-from direction and runway heading.

Crosswind = V × sin(θ) · Along-runway component = V × cos(θ)
θ = 0° gives a direct headwind · 90° gives pure crosswind · 180° gives a direct tailwind
Use the smallest separation: 0° = direct headwind, 90° = perpendicular, 180° = direct tailwind.
Enter a non-negative wind speed and an angle from 0° to 180°. Invalid or incomplete values produce no result.

Turn runway and wind directions into the angle this tool needs

The calculator does not ask for two headings; it asks for their smallest angular separation. If the runway heading is 270° and the wind is from 300°, the separation is 30°.

difference = |wind direction − runway heading|
if difference > 180°, use 360° − difference

Example: runway 030° with wind from 330° gives |330 − 30| = 300°. The smaller separation is 360° − 300° = 60°.

Keep the runway heading and wind direction referenced to the same north reference. In U.S. operations, tower and ATIS/ASOS/AWOS voice winds are reported relative to magnetic north, while coded METAR wind direction is referenced to true north. Mixing those directly can change the component calculation.

What the sine and cosine are separating

Wind speed is a vector. Relative to the runway centerline, that vector can be resolved into one perpendicular component and one parallel component.

Across runway
|V × sin(θ)|
Along runway
V × cos(θ)

For 0° ≤ θ < 90°, the parallel component is a headwind. At 90° it is zero. For 90° < θ ≤ 180°, the cosine is negative, so the parallel component is a tailwind. Because this calculator accepts only the unsigned 0°–180° separation, it reports crosswind magnitude rather than left-versus-right crosswind.

Check case: runway 27, wind 300° at 20 knots

Treating 270° as the runway heading for this worked example, the wind angle is 30°.

Crosswind = 20 × sin(30°) = 10.000000 kt
Headwind = 20 × cos(30°) = 17.320508 kt

Those numbers are the geometric components only. The calculator deliberately does not label 10 knots “safe,” “moderate,” or acceptable for a particular aircraft.

Why there is no universal crosswind warning band

A component value by itself does not establish an operating limit. Applicable limits and guidance depend on the aircraft, its approved documentation, operator procedures, runway condition, gusts, pilot qualification and experience, and other operational factors.

A published maximum demonstrated crosswind component is not a generic threshold that can be transferred from one aircraft to another. Use the AFM/POH and applicable operating rules for the specific aircraft rather than a website-wide color category.

Gusts and variable direction are not one fixed vector

This calculator evaluates one wind speed and one angle at a time. A gusting or directionally variable report describes changing conditions, so one calculation cannot represent every possible instantaneous component.

To explore a gust, calculate it separately using the gust speed. If direction is reported as varying through a range, examine the relevant endpoints or other operationally appropriate cases rather than assuming the steady-wind result is the maximum crosswind.

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