Navigation Calculations
Navigation calculators for course, bearing, distance, position, and related marine navigation calculations. Use these tools to work with common navigation measurements and planning relationships.
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Distance to Horizon Calculator
Find how far the horizon is from your height of eye. Uses the standard nautical formula for horizon distance.
Use calculator →Great Circle Distance Calculator
Compute the shortest distance between two locations on Earth using latitude and longitude. Results in nautical miles and kilometers.
Use calculator →Sailing Time Calculator
Estimate how long it will take to cover a given distance at a constant speed. Supports nautical miles, km, miles, knots, km/h, and mph.
Use calculator →Initial Bearing Calculator
Compute the initial true bearing from one lat/lon waypoint to another (the great-circle route's starting bearing).
Use calculator →Rhumb Line Distance Calculator
Approximate rhumb-line distance in nautical miles between two positions (plane sailing at mean latitude).
Use calculator →Geographic Range of a Light Calculator
Estimate combined geographic visible range (nm) from height of eye and light elevation.
Use calculator →Radar Horizon Calculator
Approximate radar line-of-sight horizon in nautical miles from antenna height.
Use calculator →Latitude Degrees to Nautical Miles
Convert degrees of latitude (or longitude at the equator) to nautical miles along a meridian.
Use calculator →Current Drift Distance Calculator
Distance run by set in nautical miles: current speed × time in hours.
Use calculator →Longitude Minutes to Nautical Miles
Nautical miles per minute of longitude at a given latitude (cosine scaling).
Use calculator →True from Magnetic Heading
True heading = magnetic heading + easterly variation (subtract westerly).
Use calculator →Cross Track Error Calculator
Approximate XTE in nm from distance run along track and bearing error.
Use calculator →Speed Over Ground Calculator
Vector sum of speed through water and current using law of cosines.
Use calculator →Mercator Scale Factor Calculator
Chart scale exaggeration k = sec(φ) at a given latitude.
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