Knots Speed Converter
Enter a speed in knots, mph, km/h, or m/s and read it in every other unit — the quick, exact conversion for a speed log, a weather forecast, or a passage plan.
Why the sea keeps its own speed unit
A knot ties speed directly to the chart. Because a nautical mile is one minute of latitude, a navigator can step a pair of dividers up the side of the chart to read distance, and a speed in knots turns that distance into a time without any conversion. Ashore, the same speed reads more naturally in mph or km/h — which is where this converter earns its keep, translating a forecast wind or a ship’s speed into whichever unit the moment calls for.
Once you have a speed, turn it into a passage time or a distance with the Nautical Distance & ETA Calculator.
Frequently Asked Questions
What exactly is a knot?
A knot is one nautical mile per hour. A nautical mile is 1,852 metres — the length of one minute of latitude — which is why speed and distance at sea are measured in knots and nautical miles rather than miles or kilometres. One knot is therefore exactly 1.852 kilometres per hour and about 1.15078 statute miles per hour.
How do I convert knots to miles per hour in my head?
Multiply knots by roughly 1.15 for statute miles per hour, or by 1.852 for kilometres per hour. So 20 knots is about 23 mph or 37 km/h, and 10 knots is about 11.5 mph or 18.5 km/h. The converter uses the exact factors rather than the rounded ones, so the figures it gives are precise.
Why does a ship's speed matter in knots and not mph?
Because distance at sea is worked in nautical miles, a speed in knots divides straight into a distance in nautical miles to give a time — 60 nautical miles at 10 knots is exactly 6 hours, with no conversion factor. That clean relationship is why charts, logs, and passage plans all use knots and nautical miles together.
Is a knot the same as a nautical mile?
No — a nautical mile is a distance (1,852 metres) and a knot is a speed (one nautical mile per hour). Saying 'knots per hour' is a common slip; a knot already includes the 'per hour'. To find a distance, multiply speed in knots by time in hours; to find a time, divide distance in nautical miles by speed in knots.
Uses the exact 1 kn = 1.852 km/h and 1 mile = 1.609344 km definitions. An educational converter — always work to the ship’s own instruments for navigation.