Marine Speed Distance Time Calculator
Speed, distance, and time are bound together by one simple identity that underpins almost every navigation estimate: speed is distance over time. In marine navigation distance is measured in nautical miles, speed in knots, and time in hours or minutes, all kept consistent with the latitude scale on the chart. This calculator solves the relationship three ways at once. Enter a distance with a speed to get the time it takes, enter a distance with an elapsed time to get the speed made good, and enter a speed with a time to get the distance covered. Useful for estimated times of arrival, watch planning, and dead reckoning.
Speed, distance, time formula
Time (hr) = distance (nm) / speed (kt); minutes = hours * 60
Speed (kt) = distance (nm) / time (hr)
Distance (nm) = speed (kt) * time (hr)
Time in minutes is converted to hours by dividing by 60
A nautical mile is 1,852 metres and a knot is one nautical mile per hour, so these units stay consistent with the chart's latitude scale.
Marine navigation notes
- Keep distance in nautical miles and speed in knots to match the chart latitude scale.
- The relationship gives speed and distance through the water, not over the ground.
- Combine with current set and drift separately to find speed and course made good.
- For estimated time of arrival, add the time from distance and speed to your departure time.
- The 60 D Street memory aid: distance equals speed times minutes divided by 60.
Speed, distance, time: frequently asked questions
What is the speed, distance, and time formula?
Speed equals distance divided by time, distance equals speed times time, and time equals distance divided by speed. In marine navigation distance is in nautical miles, speed in knots (nautical miles per hour), and time in hours or minutes. The relationship is sometimes remembered as the 60 D Street rule, distance equals speed times time over 60 when time is in minutes.
What is a knot?
A knot is one nautical mile per hour. A nautical mile is defined internationally as 1,852 metres and approximates one minute of latitude. Because charts and latitude scales are in nautical miles, using knots keeps speed, distance, and time consistent with the chart for navigation.
How do I find time from distance and speed?
Divide the distance in nautical miles by the speed in knots to get the time in hours, then multiply by 60 for minutes. For example, 12 nautical miles at 8 knots takes 1.5 hours, or 90 minutes. This calculator returns the time in both hours and minutes from the distance and speed you enter.
How do I find the speed I am making good?
Divide the distance run by the time taken. If you covered 6 nautical miles in 45 minutes, convert 45 minutes to 0.75 hours, then divide 6 by 0.75 to get 8 knots. This calculator computes the speed from the distance and the elapsed time you enter.
Does this account for current and leeway?
No. The calculator gives the relationship among speed, distance, and time for whatever values you enter. To find speed and course made good over the ground, first combine your speed and heading through the water with the set and drift of the current using a separate vector solution.
Official sources
- U.S. Coast Guard Navigation Center: navigation references and standards.
- NOAA National Geodetic Survey: geodetic distance and datum information.
Reviewed by the CalculatorHub team, edited by James Graham, 17 June 2026. See our methodology.