Knots and Speed at Sea
Why speed is measured in knots and how to convert to other units.
Author: OceanCalc Editorial Team · Publisher: Albor Digital LLC
A knot is one nautical mile per hour. Because charts use nautical miles, using knots for speed keeps units consistent: distance in nm divided by speed in knots gives time in hours. The term comes from the historical chip log, where knots in a rope were used to measure speed.
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Frequently Asked Questions
How fast is 10 knots?
10 knots is about 11.5 mph or 18.5 km/h. It's a typical cruising speed for many sailboats and a common wind speed for sailing.