Crosswind Component Chart, Formula & Calculator
Crosswind = Wind speed × sin(relative angle)
Headwind/Tailwind = Wind speed × cos(relative angle)
Resolve the wind into a component across the runway and a headwind or tailwind along it. Use wind and runway directions on the same north reference.
Crosswind component formula
First find the smallest angle between the runway direction and the direction the wind is coming from. Then use:
Headwind/Tailwind = Wind speed × cos(relative angle)
The sign and geometry tell you whether the crosswind is from the left or right and whether the along-runway component is a headwind or tailwind.
Which side is the crosswind from?
Once you know the component magnitude, compare the wind direction with the runway direction. If the wind is coming from the right side of the runway centerline, the crosswind is from the right; if it is coming from the left side, the crosswind is from the left. Different calculators may use positive and negative signs differently, so do not memorize a sign convention without checking the tool’s labels.
For example, on Runway 14 (about 140°), wind from 180° is coming from the airplane’s right side. The crosswind is therefore from the right, even if a calculator displays a negative number under its own mathematical convention.
Wind components for the selected runway
Suppose Runway 18 is treated as 180° and the wind is from 220° at 20 knots. The relative angle is 40°. Crosswind is 20 × sin(40°), or about 12.9 knots. The headwind component is 20 × cos(40°), or about 15.3 knots.
If the wind were instead from 140° at 20 knots, the crosswind magnitude would still be about 12.9 knots, but it would come from the opposite side.
Quick crosswind mental-math chart
If you only need a fast reasonableness check, remember three anchors: 30° ≈ half the wind, 45° ≈ 70%, and 60° ≈ 87%. Then compare the calculator result with that mental estimate.
You can estimate the answer quickly with a few useful angle factors:
| Angle from runway | Crosswind | Headwind |
|---|---|---|
| 10° | ≈ 17% of wind | ≈ 98% |
| 20° | ≈ 34% | ≈ 94% |
| 30° | ≈ 50% | ≈ 87% |
| 45° | ≈ 71% | ≈ 71% |
| 60° | ≈ 87% | ≈ 50% |
| 90° | 100% | 0% |
At 30°, use about one-half of the wind for crosswind. At 45°, use about seven-tenths. At 60°, nearly nine-tenths. At 90°, all of the wind is crosswind. These are excellent reasonableness checks when using a calculator or FAA component chart.
How to calculate crosswind with gusts
If the wind is reported as 220° at 15 gusting 25 knots, calculate the component at 15 knots and then run the same angle again at 25 knots. With a 40° relative angle, the steady crosswind is about 9.6 knots while the gust crosswind is about 16.1 knots.
PilotDesk's calculator accepts one wind speed at a time, so simply run the calculation again using the gust value. This makes the steady and gust cases easy to compare rather than hiding the stronger component inside one number.
METAR winds vs. tower and ATIS winds
Make sure your direction references match. In U.S. aviation weather products, the coded METAR wind direction is referenced to true north. ATIS and ASOS/AWOS radio voice winds are reported relative to magnetic north, and tower-issued winds are magnetic as well. Runway numbers and runway magnetic direction are magnetic references.
For a quick training calculation, using the displayed runway number may be close enough to learn the geometry. When the result matters operationally, use current runway data and consistent true/magnetic references. See the FAA Aeronautical Information Manual weather guidance.
Runway numbers are rounded
Runway 18 does not necessarily point exactly 180°. Runway designators are rounded from magnetic orientation, and published runway information can provide a more precise direction. If the wind component is close to an aircraft, operator, or personal limit, use the current runway data instead of assuming the painted number is exact.
Which runway has the lowest crosswind?
The runway most nearly aligned into the wind usually produces the smallest crosswind and largest headwind component. But crosswind magnitude is not the only runway-selection factor. Runway length, surface, slope, traffic flow, obstacles, NOTAMs, aircraft performance, ATC instructions, and a possible tailwind all matter.
Demonstrated crosswind vs. a limitation
Do not automatically treat every POH “maximum demonstrated crosswind” value as a hard limitation. The wording and certification basis matter. Read the current POH/AFM and follow any actual aircraft or operator limitation. Personal minimums can of course be more restrictive than either.
Crosswind questions
How do you calculate crosswind component?
Multiply wind speed by the sine of the angle between the runway direction and the wind direction.
How do you calculate headwind or tailwind?
Multiply wind speed by the cosine of the relative angle. If the wind is more than 90° from the runway heading, the along-runway component is a tailwind.
What is the crosswind at 30 degrees?
At 30° off the runway, crosswind is exactly one-half the wind speed because sin(30°) = 0.5.
Do gusts change the crosswind component?
Yes. If direction stays the same and speed increases in the gust, both crosswind and along-runway components increase proportionally.
How do I know whether the crosswind is from the left or right?
Look at which side of the runway centerline the wind is coming from. Wind from the airplane’s right side is a crosswind from the right; wind from the left side is a crosswind from the left. Do not rely on an unlabeled positive or negative sign by itself.
Related PilotDesk tools
Crosswind Component Calculator · Crosswind Component Chart · Aviation Weather · Wind Triangle Calculator · METAR and TAF Guide · Online E6B · Pilot Math Formulas
Source check
The sine/cosine relationship is the same geometry represented by the FAA wind-component chart. See the FAA Pilot's Handbook of Aeronautical Knowledge, and the exact aircraft POH/AFM or operator guidance that applies.