Dead Reckoning Calculator

Dead Reckoning Calculator

Dead reckoning is the traditional navigation technique of estimating current position based on a known starting point, heading, speed, and elapsed time - without relying on GPS or other external position fixes.

Distance = Speed x Time
New position is then the great-circle destination point from the starting coordinates, given heading and distance.

Example

Starting at 25.7617, -80.1918, heading 90┬░ (due east) at 10 knots for 2 hours:

Distance = 20 nautical miles → Estimated Position: 25.76123, -79.82193

Why This Skill Still Matters

Dead reckoning remains a critical backup navigation skill in case of electronic navigation failure - every mariner learns it as a fundamental part of navigation training, even in an era where GPS is nearly universal, precisely because GPS receivers and their power sources can fail at inconvenient moments.

Accumulated Error

Dead reckoning positions accumulate error over time from unaccounted factors like current, leeway (wind-induced sideways drift), and compass or speed measurement inaccuracies - this is exactly why experienced navigators periodically take actual position fixes (via GPS, landmarks, or celestial navigation) to correct accumulated dead reckoning drift, rather than relying purely on continuous dead reckoning over long passages.