Crosswind Component Calculator

Split the wind into crosswind and headwind parts for any runway heading.

What it does

Every takeoff and landing meets wind at some angle, and runways rarely line up with it. This tool splits a reported wind into two parts: the push across the runway (crosswind) and the push along it (headwind or tailwind).

Pilots compare those two numbers against limits before rolling. A 15 kt wind sitting 50 degrees off the runway carries an 11.5 kt crosswind, which tops many training limits even though the raw speed sounds mild.

The math is plane trigonometry. Wind direction minus runway heading gives the angle; the sine of that angle scales the wind into crosswind, the cosine into headwind. A wind straight down the runway leaves zero crosswind, and a wind at 90 degrees is all crosswind.

Reports give direction as the place the wind comes from: wind 270 blows from the west. This tool marks the side in plain words, left or right, which is what you feel through the controls. Gusts deserve a second run through the same math, because the gust value is what breaks traction.

This page shows the full method, one hand checked example for the default wind, a reference table of angle shares, and practice checks that run through the tool.

How to use

1. Pick knots or km/h to match the weather report.
2. Enter the steady wind speed.
3. Enter the wind direction it comes from.
4. Enter the runway heading, the number times ten.
5. Read the crosswind and head or tail values.
6. Run the gust value through the same steps for the worst case.

Formula

angle

Wind direction minus runway heading, wrapped to -180 to 180 degrees.

sin

Sine of the angle, the crosswind share of the wind.

cos

Cosine of the angle, the along runway share.

A wind from the right gives a positive crosswind here, and a positive headwind means the wind blows toward you down the runway. Direction is the source, so wind 270 against runway 270 is a pure headwind. Gust spread adds to the crosswind case, and published checks suggest a 15 degree angle keeps a quarter of the wind for the crosswind, so modest angles are not free.

Worked example

Reference table

Limits

• Steady wind only. Gusts, shear, and mechanical turbulence need their own margin.
• Assumes both headings use the same reference; mixing true and magnetic shifts the angle.
• No aircraft data inside. Limits come from the POH and your own training.
• Crosswind on a wet or icy runway behaves nothing like the dry number.

Common mistakes

• Swapping the wind direction and runway heading, which flips left and right.
• Testing only the average wind and skipping the gust case.
• Treating 30 degrees as mild when it keeps half the wind as crosswind.
• Mixing a true heading with a magnetic wind report in one pass.
• Forgetting that tailwind limits are often lower than crosswind limits.

Try it yourself

Quick checks. Answers sit tucked under each question.

Questions

Sources

• FAA Airplane Flying Handbook, chapter 9: approaches and crosswind technique
• UPC master thesis with takeoff and landing wind component equations (vc = v sin delta)

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