The wind almost never blows straight down the runway. What matters for control is the component across it, and what matters for performance is the component along it. This calculator resolves any reported wind into both, for any runway heading — the same arithmetic every pilot runs before choosing a runway.
How this calculator works
Crosswind is wind speed multiplied by the sine of the angle to the runway heading.
Worked example
Runway 27 with wind from 320° at 18 kt is a 50-degree off-axis wind: about 14 kt of crosswind and 12 kt of headwind. For many light singles, 14 kt sits right at the demonstrated crosswind figure — a useful thing to know before joining the circuit rather than on final.
Frequently asked questions
How do I estimate crosswind without a calculator?
Use the clock rule: an angle of 15 degrees off the runway gives a quarter of the wind speed as crosswind, 30 degrees gives half, 45 degrees three quarters, and 60 degrees or more counts as the full wind speed. It errs slightly conservative, which is the right direction to err.
What is the demonstrated crosswind limit?
The crosswind a test pilot showed during certification — typically 12–20 kt for light singles. It is not a legal limit, but it is the manufacturer's proven envelope, and personal limits for pilots who are not current on gusty crosswinds sensibly sit below it.
When does the along-runway component become a tailwind?
Whenever the wind is more than 90 degrees off the runway heading. Most types limit tailwind operations to around 10 kt, and the performance penalty is severe — a few knots of tailwind can add a quarter to the landing distance, which is why the other runway direction usually wins.
What to verify next
- Approved aircraft documentation and current limitations.
- Local fuel, insurance, maintenance, hangar and financing quotations.
- The exact aircraft configuration, loading and maintenance status.