How are the components calculated?

The tool finds the angle between the wind direction and the runway heading, then multiplies wind speed by the cosine of that angle for the headwind and the sine for the crosswind. This is standard vector resolution of the wind onto the runway axis.

What does a negative headwind mean?

A negative headwind is a tailwind, meaning the wind has a component pushing you along the runway rather than against you. The tool flags this in red because a tailwind lengthens the takeoff and landing roll and may exceed aircraft limits.

Which way should I enter wind direction?

Enter the direction the wind blows from, exactly as reported in a METAR or ATIS. A wind of 300 degrees means the air is coming from the northwest, even though it then moves toward the southeast.

Should I use the gust value for the limit check?

Yes. Crosswind limits should be checked against the gust, not just the steady wind, because a gust can briefly exceed your control authority on the runway. The tool computes the crosswind component of the gust separately when you enter it.

Is this magnetic or true heading?

Runway numbers and METAR winds at most airports are both referenced to magnetic north, so enter magnetic values and the result is consistent. If you mix a true wind with a magnetic runway you will introduce an error equal to local magnetic variation.

Crosswind & Headwind Component Calculator

Picking the right runway and staying inside your aircraft’s crosswind limit both depend on splitting the reported wind into the part that blows down the runway and the part that blows across it. This calculator resolves any reported wind into headwind and crosswind components for the runway heading you choose.

How it works

The wind is treated as a vector. The angle between the wind direction and the runway heading determines how much of the wind acts along the runway versus across it:

angle      = wind direction − runway heading   (signed, −180 to 180)
headwind   = wind speed × cos(angle)            (negative = tailwind)
crosswind  = wind speed × sin(angle)            (sign = left or right)

A wind nearly aligned with the runway is almost all headwind; a wind 90 degrees to the runway is almost all crosswind. The sign of the crosswind tells you whether it comes from the left or right.

Example and notes

Landing on Runway 27 (heading 270) with wind reported 300 at 18 knots gives an angle of 30 degrees: headwind is 18 × cos 30° ≈ 15.6 kt and crosswind is 18 × sin 30° = 9.0 kt from the right. Always check the crosswind against the gust value, not the steady wind, and compare it to your aircraft’s demonstrated crosswind limit. If the headwind shows as negative you have a tailwind and should consider the reciprocal runway.