Navigation Formulas

Density Altitude Formula

Calculate density altitude from pressure altitude and outside air temperature. Critical for aircraft performance planning at high elevations or in hot weather.

Hull Speed Formula

Calculate the theoretical maximum speed of a displacement hull from its waterline length. Used in sailboat and powerboat design and performance estimation.

Tidal Height Formula — The 1/12 Rule

Calculate the height of tide at any time using the 1/12 rule. Estimates water depth between high and low tide in 6 equal hourly steps.

True Airspeed Formula (TAS)

Convert Calibrated Airspeed (CAS) to True Airspeed (TAS) using altitude and outside air temperature. Essential for accurate flight planning.

Course Made Good Formula

Calculate course made good (CMG) — the actual direction traveled accounting for current, wind, or leeway. Essential for marine and aviation navigation.

ETA Formula (Estimated Time of Arrival)

Calculate estimated time of arrival using distance, speed, and departure time. Essential for navigation, shipping, flight planning, and logistics.

Wind Correction Angle Formula

Calculate the wind correction angle (WCA) for aviation navigation. Correct your flight heading to compensate for crosswind drift using the WCA formula.

Cross-Track Distance Formula

Calculate how far off course a vessel or aircraft has drifted from the intended route. Uses angular distance and bearing difference.

Dead Reckoning Formula

Calculate your current position from a known starting point using heading, speed, and elapsed time. A fundamental navigation technique.

Rhumb Line Distance Formula

Calculate rhumb line distance for constant-bearing navigation on a Mercator projection. Used in maritime and aviation navigation.

Haversine Formula

Reference for the Haversine formula for great-circle distance between GPS coordinates in km and miles. Covers bearing calculation and midpoint formula.

Bearing Formula

Reference for the bearing formula using atan2 to calculate true compass heading between two lat/lon points. Covers true vs magnetic bearing.

Great Circle Distance

Calculate the shortest path between two points on Earth using the Haversine formula. Used in aviation, shipping, and GPS for accurate great circle routing.

Haversine Formula

Reference for the Haversine formula calculating great-circle distance between two lat/lon coordinates on Earth. Used in GPS, flight, and mapping apps.

Magnetic Declination Formula

Reference for magnetic declination — the angle between true and magnetic north. Explains east and west corrections for compass bearings in hiking and sailing.

Speed, Distance, Time Formula

Calculate speed, distance, or travel time from the other two using d = s × t. Covers unit conversions for mph, km/h, meters per second, and knots navigation.