Crosswind component calculator

How do you calculate a crosswind component?

Find the angle between the runway heading and the direction the wind is blowing from. The crosswind component is the wind speed times the sine of that angle; the headwind component is the wind speed times the cosine. Runway 27 has a heading of 270 degrees. A wind from 300 degrees at 20 knots is 30 degrees off the nose: crosswind = 20 × sin 30° = 10.0 knots from the right, headwind = 20 × cos 30° = 17.3 knots.

Which way is the crosswind coming from?

Imagine looking down the runway in the direction of landing or takeoff. If the wind's direction is clockwise from the runway heading by less than 180 degrees, the crosswind comes from your right; if it is counterclockwise, from your left. The calculator shows the side and the angle, and a negative headwind is a tailwind. With the wind from 090 on runway 27 the angle is 180 degrees, so a 10-knot wind is a 10-knot tailwind and no crosswind at all.

What is the maximum demonstrated crosswind component?

It is the strongest 90-degree crosswind in which the manufacturer's test pilots flew the airplane during certification, and it appears in the pilot's operating handbook. The FAA Airplane Flying Handbook says an airplane must be shown to be controllable, without exceptional skill or alertness, in 90-degree crosswinds up to 0.2 times its stall speed in the landing configuration (V_SO), and that this value is placarded on airplanes certificated after May 3, 1962. For an airplane with a V_SO of 49 knots that is 9.8 knots. FAA Safety adds that the figure is not a limitation: the airplane may handle more, but nobody tested it.

How do I include gusts?

Run the calculation twice, once with the steady wind and once with the gust speed, and judge the gust figure against your limit. With the wind from 300 degrees on runway 27 the steady 20 knots give 10.0 knots of crosswind and a gust to 30 knots gives 15.0. For the approach, the FAA handbook says pilots often add half the gust factor to the normal approach speed: its example is a 70-knot approach speed and 15-knot gusts, 77 knots. Here the gust spread is 10 knots, so the increment is 5.0 knots. Always follow the airplane's POH or AFM for the final speed.

Can I enter the runway number instead of the heading?

Yes. Type 27 for runway 27 (270 degrees) or 270; any number from 1 to 36 is read as a runway number and larger numbers as a heading in degrees. Runway numbers are the heading rounded to tens of degrees, so use the exact magnetic heading if the runway is not aligned to a multiple of ten. A heading of 0 or 360 is north.

Is the wind in a METAR true or magnetic?

The FAA's Pilot's Handbook of Aeronautical Knowledge says the wind in a METAR is the direction the true wind blows from, while a runway number is a magnetic heading. They differ by the local magnetic variation, so convert one to the other before you enter the numbers, or use a wind that is already given in the same reference as the runway. The calculator takes whatever reference you give it for both numbers.

What crosswind is too much?

There is no universal number. The limit depends on the airplane, the loading, the runway width and surface, the gusts, and above all the pilot. FAA Safety recommends pilots set personal minimums for wind and document their own performance with an instructor; the airplane's demonstrated value is a starting point, not a target. The Airplane Flying Handbook is blunt that it is imperative for pilots to determine the maximum crosswind component of each airplane they fly and avoid wind conditions that exceed the airplane's capability.

The formula and the angle table

With the angle θ between the runway heading and the wind direction, crosswind = V × sin θ and headwind = V × cos θ. Because sine rises quickly at small angles, a wind well off the runway adds crosswind faster than most people expect. For a 100-knot wind the crosswind is 17 knots at 10 degrees, 26 knots at 15 degrees, 34 knots at 20 degrees, 50 knots at 30 degrees, 71 knots at 45 degrees, 87 knots at 60 degrees, 97 knots at 75 degrees, 100 knots at 90 degrees; the matching headwinds are 98, 97, 94, 87, 71, 50, 26, 0 knots. In ordinary terms: at 30 degrees the crosswind is half the wind, at 45 degrees about 70 percent, and from 60 degrees almost all of it.

Worked example

Runway 27 (heading 270 degrees), wind 300 degrees at 20 knots gusting to 30, your airplane's demonstrated crosswind is 15 knots. Angle: 300 − 270 = 30 degrees, from the right. Steady crosswind 10.0 knots (67 percent of the demonstrated value), gust crosswind 15.0 knots (100 percent). The wind at this angle reaches the 15-knot figure at 30.0 knots, so the gusts are just at it, a good reason to look at another runway if the airport has one. Wrap-around: runway 36 with the wind from 350 degrees is 10 degrees to the left, not 350.

Common mistakes

Reading the wrong end of the runway is the classic one: the same wind is a headwind on one end and a tailwind on the other, so the table at the bottom of the result shows both. Mixing true and magnetic directions is another, as is using the steady wind when the gust is what the airplane meets at touchdown. A third is treating the demonstrated crosswind as a legal limit: the FAA calls it a testing result, not a limitation, yet it is also not a promise that the airplane can handle more.

Limits of this method

The calculation assumes a steady wind blowing straight and evenly across the runway. Real surface winds shift, gust and swirl around buildings and terrain, and wind shear or turbulence near the ground can change the effective crosswind within seconds. The result says nothing about braking action, runway width, landing distance or the pilot's recent experience. It is a quick way to check the arithmetic, not a substitute for the performance data in your aircraft's handbook.

For awareness only, not for flight planning or any operational decision: use the performance data and limitations in your aircraft’s pilot’s operating handbook or AFM and follow your instructor’s guidance. Sources, read October 27, 2026: FAA, Airplane Flying Handbook (FAA-H-8083-3C), chapter 9, “Maximum Safe Crosswind Velocities” and “Crosswind Approach and Landing”; FAA Safety, “Personal Minimums for Wind” (AFS-850); FAA, Pilot’s Handbook of Aeronautical Knowledge, chapter 13 (METAR wind reference). Related: density altitude calculator, knots to mph, wind chill calculator, trigonometry calculator. How we check our calculators.