Wind Correction Angle Calculator
Calculate wind correction (crab) angle from airspeed, wind speed, and direction.
Returns heading correction and ground speed for aviation and sailing.
When wind blows across your path of travel, you must aim into the wind to maintain a straight course over the ground. The angle you aim away from your desired track is the Wind Correction Angle (WCA), also called the crab angle.
Formula: WCA = arcsin(wind speed × sin(wind angle) / airspeed or vessel speed)
Where wind angle is measured from your desired track direction (0° = headwind, 90° = direct crosswind, 180° = tailwind).
Worked example (aviation):
- True airspeed: 120 knots
- Wind: 15 knots from 270°, flying course 360° (north)
- Wind angle relative to course: 90° (direct crosswind from the left)
- WCA = arcsin(15 × sin(90°) / 120) = arcsin(0.125) = 7.2°
- Heading to steer: 360° − 7.2° = 352.8° (turn into the wind)
Worked example (sailing / kayaking):
- Vessel speed through water: 5 knots
- Cross-current: 1.5 knots at 90°
- WCA = arcsin(1.5 / 5) = 17.5° — aim 17.5° upstream
Effective speed after correction: Ground speed = sqrt(airspeed² − (wind × sin(wind angle))²) ± wind × cos(wind angle)
Pilot rule of thumb: WCA ≈ (crosswind component / airspeed) × 60 For small angles (under 15°) this approximation is accurate within 1°.