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.

Start latitude

Required number input.

Start longitude

Required number input.

Course

Required number input.

Distance

Required number input.

Project a dead reckoning position from a start coordinate, course, and distance traveled. 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]

Latitude

The resulting latitude returned as a number.

Longitude

The resulting longitude 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.

• Cross Track Error Calculator

  Calculate the signed perpendicular distance from a desired course given distance run and the bearing back to the start point.

• 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.

• Distance to Layline Calculator

  Calculate the distance along the course centerline to a layline from the lateral offset and half of the total angle between port and starboard tacks.