Crosswind Calculator
Wind direction and speed versus your runway → exact crosswind and headwind components, from manual entry or the live METAR at any airport. Know it before you line up.
New to splitting the wind into components? Crosswind components, explained covers the formula, the clock face shortcut that gets you within a knot in your head, and why the demonstrated crosswind in your POH is a certification data point rather than a limit.
How crosswind components are calculated
The wind's angle to the runway splits it into two parts: the headwind component (along the runway) and the crosswind component (across it). With the angle between wind and runway heading:
- Crosswind = wind speed × sin(angle)
- Headwind = wind speed × cos(angle), negative means a tailwind
Worked example
Wind 210° at 20 kt, landing runway 24 (heading 240°). The wind is 30° off the runway centerline, so:
- Crosswind = 20 × sin(30°) = 10 kt
- Headwind = 20 × cos(30°) = 17 kt
Enter your runway number (e.g. 24) and the tool uses its heading (240°). Compare the crosswind result against your aircraft's maximum demonstrated crosswind and your own personal minimums.
The clock method, for when you have no calculator
Picture the angle between the wind and the runway as minutes on a clock. 15° is a quarter past, so take a quarter of the wind speed. 30° is half past, half the wind. 45° is three quarters. Anything 60° or more, count the whole wind as crosswind. It is conservative at the large angles and close enough at the small ones: the exact value at 30° is 0.50, at 45° it is 0.71, at 60° it is 0.87. Runway 24 with wind 210° at 20 kt is "half past", 10 kt, the same answer as above.
Gusts
A METAR of 21015G25KT is two winds. The steady 15 kt gives the crosswind you will
trim for on final; the 25 kt gust gives the crosswind that can arrive in the flare, and it is
the one to hold against your limit. In the example above the gust crosswind on runway 24 is
12.5 kt. The common technique adds half the gust factor to approach speed: with a 10 kt spread,
fly 5 kt faster. Enter the gust speed as the wind speed to see the worst case.
That gust spread is the part of the report that does not fit in the sine table, because it changes two numbers at once: the crosswind you have to hold, and the speed you fly the approach at. Every row below is the same approach, runway 27 with the wind from 310, so 40 degrees off the centerline. Only the report changes.
| METAR group | Steady | Gust | Gust factor | Half the factor, added to approach speed | Crosswind, steady | Crosswind, gust |
|---|---|---|---|---|---|---|
31010G15KT | 10 kt | 15 kt | 5 kt | +2.5 kt | 6.4 kt | 9.6 kt |
31012G20KT | 12 kt | 20 kt | 8 kt | +4 kt | 7.7 kt | 12.9 kt |
31015G25KT | 15 kt | 25 kt | 10 kt | +5 kt | 9.6 kt | 16.1 kt |
31018G30KT | 18 kt | 30 kt | 12 kt | +6 kt | 11.6 kt | 19.3 kt |
31020G35KT | 20 kt | 35 kt | 15 kt | +7.5 kt | 12.9 kt | 22.5 kt |
Read down the last two columns rather than across the row. The steady crosswind rises by about 6 kt from the first row to the last, which most pilots would describe as a windier day. The gust crosswind rises by 13 kt over the same five rows, which is the difference between a routine landing and one that a typical light single has never demonstrated. The gust factor is the thing that grows, and the gust factor is the column people skip.
The approach speed column has a cost of its own. Extra speed has to be dissipated on the runway, so adding 7.5 kt to the approach in the bottom row lengthens the landing roll at the same time as the crosswind is at its worst. On a long dry runway that is an easy trade. On a short or wet one it is the trade that decides whether to go somewhere else. Use the landing distance chart in your POH with the speed you actually intend to fly.
True versus magnetic
Runway numbers are magnetic. A written METAR or TAF gives wind in degrees true, so
21015KT in the text is not necessarily 210° on the compass. Tower, ATIS and AWOS
voice reports are already magnetic. In most of the US the variation is under 15°, which shifts
a 30° crosswind angle by half a clock position, but in the Pacific Northwest and New England it
reaches 15° to 20° and matters. The live mode on this page sidesteps it by working entirely in
degrees true: the METAR wind against each runway's true heading. In manual mode, enter the
magnetic direction you would hear from the tower against the runway number.
Tailwind
A negative headwind is a tailwind, and it costs more than the number suggests. The reason is that a tailwind works on the landing twice: it raises the ground speed at touchdown, and the energy the brakes have to absorb goes with the square of that speed, not with the wind. Trading a 10 kt headwind for a 10 kt tailwind is a 20 kt swing in touchdown ground speed, which is a large change in a light single whose approach speed is only 65 kt. Most POHs publish landing distance to about 10 kt of tailwind and no further, so past that figure you are extrapolating a chart rather than reading one. Take the number from the landing distance chart in your own POH; a rule of thumb is not good enough for a decision this shape. If the tool shows a tailwind on your chosen runway, work the reciprocal; every airport page shows which runway end the current wind favors.
Picking the runway, worked
The decision is rarely one runway against a limit. It is usually two runway ends against each other, and the answer is the largest headwind rather than the smallest crosswind. Here is a field with runway 01/19 and runway 13/31, and the wind from 350 at 16 kt.
- Runway 01 points 010°, so the angle to a wind from 350° is 20°. Headwind = 16 × cos 20° = 15 kt. Crosswind = 16 × sin 20° = 5 kt, from the left.
- Runway 31 points 310°, so the angle is 40°. Headwind = 16 × cos 40° = 12 kt. Crosswind = 16 × sin 40° = 10 kt, from the right.
- Runway 19 and runway 13 are the same numbers with the headwind reversed: a 15 kt and a 12 kt tailwind respectively, with the same crosswind as their reciprocals.
Runway 01 wins on both counts here, which is the usual case for a wind inside 45 degrees of a runway. What the picture is really for is the case where it does not: if 31 were twice the length of 01, or if 01 were the wet one, the 5 kt of extra crosswind on 31 would be the cheaper of the two problems. Work the components first, then decide, because the components are the only part of that decision you can get wrong by arithmetic.
What is a reasonable crosswind limit?
The POH "maximum demonstrated crosswind" is the strongest crosswind the manufacturer's test pilot landed in during certification, with no special skill required. It is typically 15 kt for a Cessna 172 and 17 kt for a Piper Archer. It is not a limitation, but a student pilot is usually restricted to something well below it by their instructor, and a rusty pilot should be too. The personal minimums tool keeps your own number, and the explainer covers how to set it.
Related
Winds aloft, rather than surface wind, decide your heading and ground speed en route: the E6B flight computer solves that wind triangle. To check the wind at a specific field right now, the live mode here or the field's SkyReady airport page both read the current METAR.
FAQ
Is the maximum demonstrated crosswind a limit?
For most light aircraft it's not a regulatory limit, but it's the most that was demonstrated during certification, a strong reference point. Your personal minimum should usually be at or below it.
Do I use the steady wind or the gust for the crosswind component?
Compute both. The steady value is what you will hold on final; the gust value is what can hit you in the flare. Most pilots compare the gust crosswind against their limit, and add half the gust factor to approach speed.
Is METAR wind true or magnetic?
A METAR or TAF reports wind in degrees true. Tower, ATIS and AWOS voice broadcasts give it in magnetic, which is what runway numbers use. The difference is the local variation, up to about 20 degrees in parts of the US, so a written METAR wind should be corrected before comparing it with a runway number. The live mode on this page avoids the problem by comparing the METAR wind with each runway's true heading.
Can it use live wind for a specific airport?
Yes. Switch to "Live airport wind", enter the ICAO code, and the tool loads the current METAR wind and the airport's real runways, then shows the components for every runway end. You can also open it directly with /tools/crosswind?icao=KLVK.
What is a quick mental crosswind estimate?
The clock method: treat the angle between wind and runway as minutes on a clock face. 15° off is a quarter of the wind, 30° is half, 45° is three quarters, and 60° or more is all of it. Wind 20 kt at 30° off the runway is roughly 10 kt of crosswind; the exact figure is also 10 kt.
Should the headwind and crosswind components add up to the wind speed?
No, and a pair that does add up is a sign of arithmetic gone wrong. They are the two legs of a right triangle whose hypotenuse is the wind, so they combine in quadrature: 10 kt across and 17.3 kt down a runway is the square root of 100 plus 299, which is the 20 kt wind you started with. The practical consequence is that the crosswind grows slowly at first. At 20 degrees off the runway you still keep 94 percent of the wind as headwind while only a third of it goes across.
Does the runway number itself introduce an error?
A little. Runway numbers are the magnetic heading rounded to the nearest ten degrees, so runway 09 can point anywhere from 085 to 094 and the number can be up to 5 degrees off the real heading. With a 20 kt wind 30 degrees off the runway, 5 degrees of error moves the crosswind between 8.5 and 11.5 kt, so about 1.5 kt either way. That is noise next to the gust spread most days, and it matters when you are sitting on your limit. The live mode on this page uses each runway's charted true heading rather than its number.
Which runway do I choose when the wind sits between two of them?
Take the largest headwind component, not the smallest crosswind, then check the result against the runway itself. Length, width, surface condition and the traffic already in the pattern can all outweigh a few knots of component. A tailwind component is the one to be strict about: most handbooks publish landing data only to about 10 kt of tailwind, so beyond that you are extrapolating performance rather than reading it.
Sources: FAA Airplane Flying Handbook (FAA-H-8083-3C), chapter 8, on crosswind approaches and landings and on the gust additive; FAA Pilot's Handbook of Aeronautical Knowledge (FAA-H-8083-25C); FAA Advisory Circular AC 00-45 (Aviation Weather Services) for the wind groups in a METAR being referenced to true north; 14 CFR 91.9 on operating limitations. Where the demonstrated crosswind sits in certification is covered in the explainer. Educational material. The landing distance chart and the limitations section of your own POH or AFM decide the flight.