Speed Distance Time Calculator

Calculate speed, distance, or time for marine navigation. Enter any two values to find the third. Works in knots and nautical miles.

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Visualization

How It Works

Speed = Distance / Time. This is the fundamental navigation equation (D = S x T). In marine navigation, always use knots for speed and nautical miles for distance. One knot = one nautical mile per hour. To estimate ETA, divide remaining distance by your speed over ground (SOG) from GPS. Current and wind can make your SOG differ significantly from your speed through water (STW).