About the Crosswind Calculator
This tool resolves a wind report into two components relative to a runway: the part that blows across it (crosswind) and the part that blows along it (headwind or tailwind). Pilots use this split to decide whether landing or takeoff conditions are within their own limits and the aircraft's published limits.
The formula
Let the angle between the wind direction and the runway heading be angle = wind direction − runway heading (normalized to −180°…180°). Then:
- Crosswind component = Wind Speed × sin(angle) — the part of the wind pushing sideways across the runway.
- Headwind/Tailwind component = Wind Speed × cos(angle) — the part of the wind blowing along the runway; positive is a headwind, negative is a tailwind.
Runway headings are usually given as a two-digit runway number, which is the magnetic heading rounded to the nearest 10 degrees and divided by 10. Runway 27 has a heading near 270°, Runway 9 near 90°, and Runway 18 near 180°. Enter the full heading in degrees for the most accurate result.
Reading the results
A crosswind near 0 means the wind is blowing almost straight down the runway — an ideal alignment. A crosswind close to the full wind speed means the wind is blowing almost straight across the runway, which is the most demanding case for landing and takeoff. The angle-off-runway value (0° to 180°) shows how far the wind is from being straight down the runway, and the wind-type label describes whether it is a direct headwind/tailwind, a quartering headwind/tailwind, or a direct crosswind.
Frequently Asked Questions
How is the crosswind component calculated?
Crosswind component equals wind speed multiplied by the sine of the angle between the wind direction and the runway heading: Crosswind = Wind Speed × sin(angle). The headwind or tailwind component uses cosine instead: Headwind = Wind Speed × cos(angle). The angle is the wind direction minus the runway heading, normalized to plus or minus 180 degrees.
What runway heading should I enter?
Runway numbers are the magnetic heading rounded to the nearest 10 degrees and divided by 10. Runway 27 points roughly 270 degrees, Runway 9 points roughly 90 degrees, and Runway 18 points roughly 180 degrees. Enter the full heading in degrees, or multiply the runway number by 10 for an estimate.
What is a quartering headwind or tailwind?
When the wind angle relative to the runway is between roughly 10 and 80 degrees it is called a quartering headwind, and between 100 and 170 degrees it is a quartering tailwind, because the wind has both a crosswind and an along-runway component. A wind within about 10 degrees of straight down the runway is a direct headwind or tailwind, and a wind near 90 degrees off is a direct crosswind.
Does this tool know my aircraft's crosswind limit?
No. This calculator only computes the geometry of wind versus runway heading. Every aircraft has its own manufacturer-published maximum demonstrated crosswind component, found in the pilot's operating handbook, and pilots should compare the calculated crosswind against that limit and their own currency before deciding whether conditions are suitable.