Leeway Correction Calculator
Wind pushes a vessel sideways, so the track it actually makes through the water lies a few degrees downwind of the heading it is steering. That offset is the leeway angle. To find the course made good through the water you apply the leeway angle to leeward: subtract it when the wind is on the starboard bow, add it when the wind is on the port bow. Enter your steered heading, the leeway angle you estimate, and the wind side, and this calculator returns the water track, normalised to 0 to 360 degrees.
Leeway correction formula
Wind on starboard: track = heading - leeway
Wind on port: track = heading + leeway
Normalise: track = (track + 360) mod 360
Leeway always pushes the vessel to leeward, so the water track lies downwind of the heading. The result is wrapped back into the 0 to 360 degree range. Apply current set and drift separately to get the course over the ground.
Leeway notes
- Leeway is applied to the heading; current set and drift are applied after, to get the ground track.
- Estimate leeway by sighting the angle of your wake relative to the centreline.
- Leeway grows with wind strength and falls as boat speed rises.
- Sailing vessels close-hauled in fresh wind can see 10 degrees or more of leeway.
- Because no instrument reads leeway directly, treat the angle as an informed estimate.
Leeway correction: frequently asked questions
What is leeway in navigation?
Leeway is the sideways drift of a vessel caused by wind pushing on the hull, rig, and superstructure. The boat moves slightly downwind of the direction it is pointing, so the track through the water differs from the heading by the leeway angle. Leeway is measured in degrees.
How do I apply leeway to my heading?
Leeway pushes the vessel to leeward (downwind). If the wind is on the starboard side, the track is to port of the heading, so you subtract the leeway angle; if the wind is on the port side, you add it. This calculator applies the leeway angle on the side you select to give the course made good through the water.
How big is the leeway angle?
Leeway depends on hull shape, sail area, wind strength, and speed. It is often only a few degrees for a powered vessel making good speed, but can reach 10 degrees or more for a sailing yacht close-hauled in a strong breeze or a slow vessel in heavy weather. Estimate it from your wake angle and enter it here.
Is leeway the same as set and drift?
No. Leeway is wind-driven sideways slip through the water and is applied to the heading. Set and drift describe the movement of the water itself (current or tide) and are applied separately to convert the water track into the ground track. Apply leeway first, then current, for the course over ground.
How do I estimate my leeway angle?
A common estimate is to sight along your wake: the angle between the centreline (heading) and the wake astern is roughly the leeway angle. Some navigators use empirical tables based on wind force and boat speed. Because it cannot be read from an instrument, enter your own estimate as an input.
Official sources
- U.S. Coast Guard Navigation Center: Navigation Center.
- NOAA Office of Coast Survey: Nautical Charts.
Reviewed by the CalculatorHub team, edited by James Graham, 17 June 2026. See our methodology.