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Dead reckoning position
The dead reckoning position after a course and distance (or speed and time) from a known position.
Fill in the fields to see the result.
How it works
Change of latitude = distance × cos(course). Change of longitude = distance × sin(course) / cos(latitude) for short runs (plane and mid-latitude sailing); this tool uses Mercator sailing, d.long = tan(course) × difference of meridional parts, which stays correct for long runs and high latitudes.
A DR position ignores current and leeway (that is the estimated position, EP). Positions are worked on a sphere.
For training and cross-checking. Not a substitute for approved navigation equipment, nautical publications and the ship’s own procedures. Calculations run in your browser and nothing you type is stored; a PDF you download is made on our server and not kept.
More tools
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- Compass error
- Great circle and rhumb line
- Speed, distance, time and ETA
- Current triangle
- Compass error by the sun
- Sunrise, sunset and twilight
- Distance off
- Sextant altitude and noon latitude
- Required speed for an ETA
- CPA and TCPA
- True wind
- Horizon and light range
- MLC hours of rest
- Ship’s clocks and time zones
- IMO and MMSI number check
- Dock water allowance and loading
- Height of tide
- Mean draught and trim
- GM from rolling period
- Squat and under-keel clearance
- Anchoring
- Search patterns (IAMSAR)
- Fuel consumption and endurance
- Speed and consumption
- Propeller slip
- Indicated power
- Bunker quantity
- Fuel heating temperature
- Cylinder oil feed rate
- Electrical power
- Pay and contract dates
- Unit and position converter
- Signal flags and phonetic alphabet
- COLREGs lights and shapes
- Beaufort and sea state scales
- Marine VHF channels