Use this sailing calculation as a planning or educational cross-check for navigation, wind and current, rig loads, stability, anchoring, tides, visibility, performance, or recovery under explicitly stated conditions.

Vessel course

Required number input.

Vessel speed

Required number input.

Current set

Required number input.

Current speed

Required number input.

Calculate the resulting course over ground from vessel motion combined with current set and drift. The tool evaluates the supplied inputs together and returns the named outputs below; it does not infer omitted operating conditions or change the units shown.^[1]

Course over ground

The resulting course over ground returned as a number.

• Actual conditions change with vessel design and loading, sea state, wind, current, tide datum, weather, chart accuracy, equipment, crew, regulations, and safety margins. Simplified formulas do not replace seamanship, approved stability data, or current navigation information.
• Use finite inputs in the displayed units and preserve more precision than the final presentation requires. Independently verify safety-critical, financial, compliance, or production decisions.

Cross-check official charts, tide and weather services, instrument data, vessel manuals, and collision regulations; maintain conservative margins and a safe alternative plan.

• Speed Over Ground Calculator

  Calculate the resulting speed over ground from vessel motion combined with current set and drift.

• Set and Drift Correction Calculator

  Calculate current set and drift by subtracting the vessel's through-water velocity vector from its observed over-ground velocity vector.

• Current Gain Loss Calculator

  Calculate the distance gained or lost to the current along the course, with a favorable set positive and an adverse set negative.