Calculators › Crosswind calculator
Crosswind calculator
The headwind, tailwind and crosswind on each runway, and which one is most into wind.
Wind and runways
Load an airport’s latest report, or type your own values. Results update as you type.
Optional. Don’t know the code? Use the airport search.
How crosswind is worked out
Take the angle between the wind and the runway. The wind then splits into two parts:
- Crosswind = wind speed × sin(angle)
- Headwind = wind speed × cos(angle), which is a tailwind when the wind comes from behind
Say the runway is 27 and the wind is 300° at 20 kt. The angle is 30°, so the crosswind is 20 × 0.5 = 10 kt from the right, and the headwind is 20 × 0.87 = 17 kt.
A rule of thumb you can do in your head
| Wind angle | Crosswind is about |
|---|---|
| 30° | half the wind speed |
| 45° | three-quarters |
| 60° | seven-eighths |
| 90° | all of it |
Which runway is best?
Aircraft take off and land into wind, so the end with the most headwind is normally the one in use. In very light wind, noise rules and traffic flow decide instead, which is why the calculator doesn’t name a best runway under 3 kt. A tailwind over 5–10 kt or a crosswind of 20–30 kt reaches the limits of many aircraft, so the table flags tailwinds above 5 kt and crosswinds from 20 kt.
True or magnetic?
A METAR gives the wind in degrees true, while runway numbers and the wind a tower reads out are magnetic. Compare like with like. When you load an airport, the calculator uses the runways’ true headings to match the METAR. When you type a runway number, it uses that number × 10, so give it the magnetic wind.
Quick answers
How do you calculate crosswind?
Multiply the wind speed by the sine of the angle between the wind and the runway. A 20 kt wind 30° off the runway gives 20 × 0.5 = 10 kt of crosswind.
What is the headwind component?
The part of the wind blowing straight down the runway: wind speed × the cosine of the angle. A negative answer means it’s a tailwind.
How much crosswind is too much?
It depends on the aircraft and the runway, and the aircraft’s own manual sets the figure. Small training aircraft often have a demonstrated crosswind near 15 kt, and airliners are typically in the 30s of knots.
Is METAR wind true or magnetic?
True. The wind a tower or ATIS reads out, and the runway numbers, are magnetic, so the two can differ by the local variation.
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For training and simulation only. These calculators are for learning and for games. Their results are automatic, and they don’t account for everything a real operation does. Never use them for real flight planning, navigation or air traffic control. Use your official charts, approved tools and procedures.
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