Crosswind Calculator – Calculate Crosswind, Headwind & Tailwind Components
The crosswind calculator finds the crosswind, headwind, and tailwind components of any wind by comparing wind direction and speed against your runway heading.
XWC = 20 × sin(50°) = 15.3 kts
Crosswind is 15.3 knots from the right, with a 12.9-knot headwind along runway 09.
At or above the Cessna 172 demonstrated crosswind
What Is a Crosswind Component?
A crosswind component is the part of the wind that blows perpendicular to the runway centreline. It is measured in knots, and it is always smaller than the reported wind speed unless the wind sits at exactly 90° to the runway. Two numbers produce it: the reported wind direction and the runway heading. The difference between them is the wind angle, and that angle decides how much of the wind pushes the aircraft sideways rather than straight down the runway.
The FAA requires manufacturers to publish a maximum demonstrated crosswind for every certificated aircraft, and ICAO Annex 14 uses crosswind values to decide when an aerodrome needs a second runway. Neither figure describes the wind itself; both describe the component. A pilot reading 25 knots on the ATIS is not facing a 25-knot crosswind unless that wind lies square to the runway. At 30° off the centreline the same 25 knots produces 12.5 knots of crosswind and 21.7 knots of headwind, which is a routine day for a trainer.
Every crosswind arrives paired with either a headwind or a tailwind, because a wind vector always splits into two perpendicular parts and no wind energy is lost in the split.
How To Calculate Crosswind Components
Calculate a crosswind component by multiplying wind speed by the sine of the angle between the wind and the runway. The same wind speed multiplied by the cosine of that angle returns the headwind component.
| Symbol | Meaning | Unit |
|---|---|---|
| XWC | Crosswind component, the part of the wind acting across the runway | knots |
| HWC | Headwind component, the part of the wind acting down the runway | knots |
| V | Total reported wind speed, steady or gust | knots |
| θ | Wind angle, the difference between wind direction and runway heading | degrees |
CrosswindXWC = V × sin(θ)
HeadwindHWC = V × cos(θ)
TailwindTailwind = −HWC
- Convert the runway number to a heading
Multiply the runway number by 10 to get its magnetic heading. Runway 09 faces 090°, runway 27 faces 270°, and runway 36 faces 360°.
- Read the wind direction and speed
Take the direction the wind is blowing from and its speed in knots from the ATIS, tower, or METAR. Convert a METAR direction from true to magnetic before comparing it with a runway heading.
- Find the wind angle
Subtract the runway heading from the wind direction and normalise the result to between −180° and +180°. This signed value is the wind angle θ; its sign tells you whether the crosswind comes from the left or the right.
- Apply sine for crosswind and cosine for headwind
Multiply wind speed by the sine of θ for the crosswind component, and by the cosine of θ for the headwind component. A negative cosine result is a tailwind of that magnitude.
- Repeat with the gust value
Run the same calculation using the gust speed instead of the steady speed to find the maximum crosswind to plan the approach around.
Worked example: runway 09, wind 045° at 20 knots
- Runway heading
- 090°
- Wind direction and speed
- 045° at 20 kt
- Wind angle θ
- 045° − 090° = −45°, so θ = 45° from the left
- Crosswind
- 20 × sin(45°) = 14.1 kt
- Headwind
- 20 × cos(45°) = 14.1 kt
Crosswind, headwind, tailwind, wind correction angle, and groundspeed are all set out together on the aviation wind formula sheet for anyone who wants the full reference in one place.
Crosswind Calculator Examples
Each example below solves one runway and wind pairing, with the answer stated in the heading before you open it.
Runway 09, wind 045° at 20 kt Crosswind is 14.1 knots from the left.
- Wind angle 45°
- Crosswind 14.1 kt
- Headwind 14.1 kt
Runway 09 points to a magnetic heading of 090°, and the wind sits at 045°, so the wind angle is 45° off the centreline. Sine and cosine of 45° are identical, which splits a 20-knot wind into equal 14.1-knot crosswind and headwind components. Facing east down the runway, 045° lies off the left wing, so the aircraft needs left aileron into the wind and right rudder to hold the centreline. Both components fall inside a Cessna 172 crosswind limit.
Runway 27, wind 320° at 15 kt Crosswind is 11.5 knots from the right.
- Wind angle 50°
- Crosswind 11.5 kt
- Headwind 9.6 kt
Runway 27 faces 270°, and a 320° wind lies 50° to the right of that heading. A 15-knot wind at 50° yields 11.5 knots of crosswind and 9.6 knots of headwind, so most of the wind is now working across the runway rather than down it. Facing west, 320° sits off the right wing, calling for right aileron and left rudder in the flare. Runway 32 would face this wind almost head-on and is the better choice if it is available.
Runway 18, wind 270° at 25 kt This is a full crosswind of 25 knots.
- Wind angle 90°
- Crosswind 25.0 kt
- Headwind 0.0 kt
Runway 18 faces due south at 180°, and a 270° wind strikes it at exactly 90°. Sine of 90° equals 1 and cosine equals 0, so all 25 knots act as crosswind and nothing acts along the runway. There is no headwind to shorten the ground roll and no tailwind to lengthen it. Twenty-five knots exceeds the demonstrated crosswind of every light single in the table below, so runway 27 or a diversion is the sound call.
Runway 27, wind 090° at 10 kt This is a direct 10-knot tailwind, no crosswind.
- Wind angle 180°
- Crosswind 0.0 kt
- Tailwind 10.0 kt
Runway 27 faces 270° and the wind blows from 090°, placing it 180° behind the aircraft. Sine of 180° is 0, so the crosswind component vanishes completely, while cosine of 180° is −1, turning the entire 10 knots into tailwind. Ground roll lengthens on both takeoff and landing, and groundspeed on final rises by 10 knots. Runway 09 at the same field would turn this into a 10-knot headwind, which is why runway selection matters more than technique here.
Runway 36, wind 090° at 30 kt This is a full crosswind of 30 knots.
- Wind angle 90°
- Crosswind 30.0 kt
- Headwind 0.0 kt
Runway 36 points to 360°, and a 090° wind meets it at a right angle, producing a full 30-knot crosswind with zero headwind. This is the maximum crosswind any 30-knot wind can generate against this runway. Thirty knots sits above the demonstrated figure for a Cessna 172, a Piper Cherokee and a Cirrus SR22, and near the practical handling limit of most light twins. An east-west runway would convert the same wind into a 30-knot headwind.
Crosswind Component Chart
The crosswind component chart shows crosswind and headwind values for any wind angle and speed without calculation.
| Wind angle | 5 kt | 10 kt | 15 kt | 20 kt | 25 kt | 30 kt | 35 kt | 40 kt |
|---|---|---|---|---|---|---|---|---|
| 10° | 0.9 4.9 | 1.7 9.8 | 2.6 14.8 | 3.5 19.7 | 4.3 24.6 | 5.2 29.5 | 6.1 34.5 | 6.9 39.4 |
| 20° | 1.7 4.7 | 3.4 9.4 | 5.1 14.1 | 6.8 18.8 | 8.6 23.5 | 10.3 28.2 | 12.0 32.9 | 13.7 37.6 |
| 30° | 2.5 4.3 | 5.0 8.7 | 7.5 13.0 | 10.0 17.3 | 12.5 21.7 | 15.0 26.0 | 17.5 30.3 | 20.0 34.6 |
| 40° | 3.2 3.8 | 6.4 7.7 | 9.6 11.5 | 12.9 15.3 | 16.1 19.2 | 19.3 23.0 | 22.5 26.8 | 25.7 30.6 |
| 50° | 3.8 3.2 | 7.7 6.4 | 11.5 9.6 | 15.3 12.9 | 19.2 16.1 | 23.0 19.3 | 26.8 22.5 | 30.6 25.7 |
| 60° | 4.3 2.5 | 8.7 5.0 | 13.0 7.5 | 17.3 10.0 | 21.7 12.5 | 26.0 15.0 | 30.3 17.5 | 34.6 20.0 |
| 70° | 4.7 1.7 | 9.4 3.4 | 14.1 5.1 | 18.8 6.8 | 23.5 8.6 | 28.2 10.3 | 32.9 12.0 | 37.6 13.7 |
| 80° | 4.9 0.9 | 9.8 1.7 | 14.8 2.6 | 19.7 3.5 | 24.6 4.3 | 29.5 5.2 | 34.5 6.1 | 39.4 6.9 |
| 90° | 5.0 0.0 | 10.0 0.0 | 15.0 0.0 | 20.0 0.0 | 25.0 0.0 | 30.0 0.0 | 35.0 0.0 | 40.0 0.0 |
- Crosswind 15 kt or less
- Crosswind above 15 kt
- Crosswind above 25 kt
How to read the chart
Find the wind angle in the left column, then read across to the column matching the reported wind speed. Each cell holds two numbers: the bold figure on top is the crosswind component and the smaller figure below it is the headwind component. A wind 40° off the runway at 25 knots gives 16.1 knots of crosswind and 19.2 knots of headwind. Angles above 90° are not printed because the crosswind value repeats, a wind 130° off the runway produces the same crosswind as one 50° off, differing only in that the headwind becomes a tailwind. Interpolate between rows for angles that fall between the printed values; crosswind changes by roughly 1.5 knots per 10° near the middle of the table. Amber cells sit above the demonstrated crosswind of a Cessna 172, and red cells exceed the figure for most light aircraft entirely.
The rule of sixths
The rule of sixths converts a wind angle into a fraction with no trigonometry at all. Divide the wind angle by 60, then multiply the wind speed by that fraction, capping the result at the full wind speed. A wind 20° off the runway gives two sixths, or one third of the wind speed. A wind 40° off gives four sixths. Anything at 60° or beyond counts as the whole wind speed. The rule is exact at 30°, where it returns half the wind speed and so does sine. It over-estimates above that: at 60° it returns 100% against a true 87%, and at 45° it returns 75% against a true 71%. That bias points the safe way, since the error always hands you a larger crosswind than you actually face. Use it for the runway choice and the calculator for the number you brief.
Headwind and Tailwind Explained
Headwind
Shortens the runway you needA headwind reduces takeoff ground roll and landing distance. It is the portion of the wind blowing straight down the runway toward the aircraft, and it lowers groundspeed for a given airspeed. The wing reaches flying speed sooner on takeoff and the wheels touch at a lower groundspeed on landing, so less pavement passes underneath in both cases. A common planning figure is a 10% reduction in takeoff distance for every 9 knots of headwind in a light single, though the exact chart varies by type. Headwind also steepens the approach path, which helps clear obstacles. Because sine and cosine trade against each other, the strongest headwind occurs exactly when the crosswind is smallest.
how headwind shortens your ground roll →Tailwind
Lengthens the runway you needA tailwind increases groundspeed but extends landing distance, most aircraft limit tailwind landings to 10 knots. It appears whenever the wind angle exceeds 90°, which turns the cosine term negative. The penalty is steeper than the headwind benefit: a 10-knot tailwind can add 20% or more to landing distance in a light aircraft, and it flattens the approach so obstacles clear by less. Tailwind also raises touchdown groundspeed, which lengthens the rollout and heats the brakes. Where a tailwind and a crosswind both appear, the tailwind usually decides the runway, because it has no technique that reduces it the way a slip reduces drift.
tailwind landing limits by aircraft →How Runway Numbers Relate to Wind Direction
Runway numbers represent the runway's magnetic heading divided by 10, then rounded to the nearest whole number. Runway 09 points to 090° magnetic, runway 27 points to 270°, and runway 36 points to 360°. Every runway carries two numbers that differ by 18, because the same strip of pavement can be used from either end.
This is what lets you compare a wind direction against a runway directly: both are bearings measured from magnetic north, so subtracting one from the other gives the wind angle in a single step. The rounding introduces a small error, since runway 09 may face anywhere from 085° to 094° in reality. Airport charts publish the true heading to a tenth of a degree if you need it. The reason a field's runways point where they do is the local prevailing wind, which is why the primary runway usually gives the smallest crosswind on an average day. Read more on how runway numbers are assigned.
| Runway | Magnetic heading | Points toward | Opposite end |
|---|---|---|---|
| 09 | 090° | East | 27 |
| 18 | 180° | South | 36 |
| 27 | 270° | West | 09 |
| 36 | 360° | North | 18 |
With more than one runway available, run each heading through the calculator and take the pairing with the lowest crosswind and no tailwind, or use the picking the best runway for the wind tool to rank them at once.
Using E6B and METAR Wind Data
E6B flight computer
Mechanical methodThe E6B solves the same triangle mechanically on its wind side. Set the wind direction under the true index, mark the wind speed up from the grommet, then rotate the runway heading under the index and read the crosswind across the vertical grid lines and the headwind along the horizontal ones. The answer matches the sine and cosine result to within about a knot, limited only by how finely you can read the slide. Every checkride examiner accepts it, and it needs no battery. The same wind side also solves the wind correction angle you hold en route, which answers a different question from the crosswind component you brief for landing: one keeps you on a course between waypoints, the other keeps you on a centreline.
E6B wind side walkthrough →METAR wind group
Data sourceA METAR encodes wind as five digits followed by KT, where the first three are direction and the last two are speed. 09018G26KT means 090° at 18 knots gusting 26. A VRB prefix marks a variable direction below 6 knots, and a trailing 180V240 group gives the range the direction swung through. METAR directions reference true north while runway numbers are magnetic, so apply local variation before comparing the two.
Maximum Demonstrated Crosswind by Aircraft
Maximum demonstrated crosswind is the highest crosswind a manufacturer's test pilot maintained control in during certification, it is not a hard limit.
| Aircraft | Category | Demonstrated crosswind | Notes |
|---|---|---|---|
| Cessna 172 Skyhawk | Light single | 15 kt | Demonstrated during certification; the POH lists it as information, not a limitation. |
| Piper PA-28 Cherokee | Light single | 17 kt | Varies slightly by model year and wing; check the specific POH. |
| Cirrus SR22 | High-performance single | 20 kt | Higher wing loading and a wide gear track help, but the type is directionally sensitive. |
| Boeing 737-800 | Narrow-body jet | 33 kt | Dry runway figure; reduces sharply on contaminated surfaces. |
| Airbus A320 | Narrow-body jet | 38 kt | Dry runway figure including gusts; 29 knots wet, lower on ice. |
The figure records what one test pilot achieved on a dry runway in daylight, so treat it as a capability marker rather than a certified ceiling. Insurance policies and flight schools routinely convert it into a hard limit anyway. See the full aircraft crosswind limit table.
Crosswind Landing and Takeoff Technique
Crosswind landings use either the crab method, the wing-low method, or a crab held until the flare and then converted to wing-low. All three exist to solve one problem: the aircraft must track the centreline while the wind pushes it sideways, and the wheels must be aligned with the runway at touchdown.
The crab method points the nose into the wind by the angle needed to cancel the drift, and holds the wings level. It is the more comfortable approach for passengers and the easier one to fly accurately, because nothing is crossed up. Its weakness arrives at touchdown: landing in a crab side-loads the gear, so the pilot must kick the nose straight with rudder in the last moment before the wheels meet the pavement. Airliners with long, flexible gear can absorb a small residual crab; light aircraft cannot.
The wing-low method lowers the upwind wing with aileron and holds the nose straight with opposite rudder, producing a steady sideslip that cancels the drift with the aircraft already aligned. Nothing needs to change at touchdown, and the upwind main wheel simply touches first. The cost is a cross-controlled configuration that must be held all the way down and a higher stall speed at bank. Most pilots crab down final and transition to wing-low over the threshold, which takes the strengths of both. On takeoff the input reverses in timing but not direction: hold full aileron into the wind at the start of the roll, ease it out as the ailerons gain authority, and lift off cleanly rather than letting the aircraft skip sideways.
Detail on each phase is on the crosswind landing technique in depth page and the crosswind takeoff procedure page.
Quick Crosswind Rules of Thumb
Four wind angles cover almost every crosswind estimate a pilot needs in the cockpit: 15°, 30°, 45°, and 60°. Each maps to a percentage of the reported wind speed that acts as crosswind, and each sits within about four points of the exact trigonometric answer. Memorising these four pairs lets you rank runways on the taxiway without touching a device, then confirm the number that goes into the brief with the calculator above.
20 kt wind → 5 kt crosswind
Exact value 5.2 kt
20 kt wind → 10 kt crosswind
Exact value 10.0 kt
20 kt wind → 14 kt crosswind
Exact value 14.1 kt
20 kt wind → 17 kt crosswind
Exact value 17.3 kt
More shortcuts, including the gust-factor and headwind estimates, are on the full rule-of-thumb set.
Frequently Asked Questions
Is crosswind calculated with sine or cosine?
Crosswind uses sine; headwind and tailwind use cosine. The crosswind component equals wind speed multiplied by the sine of the angle between the wind and the runway centreline. The headwind component equals that same wind speed multiplied by the cosine of the angle. Sine reaches its maximum at 90°, which is why a wind blowing straight across the runway contributes its entire speed as crosswind.
Does gust speed change the crosswind calculation?
Yes. Substituting gust speed for steady wind speed gives the maximum crosswind you should plan for, because the wind angle stays fixed while the speed rises. A 15G25 wind sitting 40° off the runway produces 9.6 knots of steady crosswind but 16.1 knots inside the gust. Fly the approach against the gust figure, not the average.
What does a negative headwind result mean?
A negative headwind result means the wind is actually a tailwind. Cosine turns negative once the wind angle passes 90°, so the along-runway component reverses sign. A headwind of −6 knots is a 6-knot tailwind. This calculator moves that value into the tailwind card rather than printing a negative number, so read whichever of the two cards is populated.
How do you know if crosswind is coming from the left or right?
Subtract runway heading from wind direction, then normalise the result to between −180° and +180°. A positive result is a crosswind from the right; a negative result is a crosswind from the left. Wind 120° on runway 09 gives +30°, a right crosswind. Wind 060° on that same runway gives −30°, a left crosswind.
What is a full crosswind?
A full crosswind occurs when the wind blows 90° to the runway, so the entire wind speed acts as crosswind. The sine of 90° equals 1 and the cosine equals 0, leaving no headwind or tailwind component whatsoever. Wind 180° at 25 knots on runway 09 is a full 25-knot crosswind. For any given wind speed this is the worst case.
Do magnetic and true wind directions matter for this calculator?
Yes, and mixing them introduces an error equal to your local magnetic variation. Runway numbers are magnetic, ATIS and tower winds are magnetic, but METAR and TAF winds are referenced to true north. Convert a METAR wind direction to magnetic before entering it. Variation is under 5° across much of the central United States but exceeds 15° in Alaska and Maine.
How accurate is this crosswind calculator?
This calculator is exact to the trigonometry, rounded to one decimal knot. It applies XWC = V × sin(θ) with no approximation, making it tighter than the rule of sixths or a printed chart. Real-world accuracy is limited by the input instead: a reported surface wind is a two-minute average taken at one sensor, and it can differ from the wind at the threshold.
Can I use this calculator with a METAR report?
Yes. Read the wind group, where the first three digits are direction and the following two are speed in knots. METAR 09018G26KT means 090° at 18 knots gusting 26, so enter 090, 18, and a gust of 26. Convert the direction from true to magnetic first, because the runway heading you are comparing it against is magnetic.
What is considered a dangerous crosswind for a small plane?
Any crosswind above the aircraft's maximum demonstrated value is the practical warning line, and for most light singles that figure is 15 to 20 knots. Risk climbs faster than the number implies once gusts enter the picture: 12 knots gusting 22 demands more control authority and quicker feet than a steady 18. Pilot currency weighs as heavily as the number.
How do you calculate crosswind without a calculator?
Use the clock method: read the wind angle as minutes on a clock face and multiply wind speed by that fraction. Thirty degrees is half the wind speed and 60° or more is nearly all of it. A 20-knot wind at 30° gives roughly 10 knots against an exact 10.0. The full set of anchor values sits on the crosswind rules of thumb page.
What's the difference between crosswind component and crosswind speed?
Crosswind component is the portion of the total wind acting perpendicular to the runway, while crosswind speed is loose shorthand pilots use for that same figure. The distinction worth holding onto is component versus reported wind speed: a 30-knot wind lying 20° off the runway is only a 10.3-knot crosswind component, a third of the number on the ATIS.
Why do pilots care about crosswind before takeoff, not just landing?
Crosswind during takeoff can lift the upwind wing and drift the aircraft off the centreline during the ground roll, exactly when the rudder is least effective at low airspeed. Rotating into a crosswind also commits you to a departure in conditions that may exceed your limits by the time you return. Checking both ends of the flight is standard practice.