Knots to Millimeters Per Second (kn to mm/s)

1 knot equals 514.4444444 millimeters per second (rounded).

1 knot = 514.4444444 millimeters per second

How to convert knots to millimeters per second

To convert knots to millimeters per second, multiply the number of knots by 514.4444444. The factor is rounded to 10 significant digits. To go the other way, multiply millimeters per second by 0.001943844492 (rounded).

millimeters per second = knots × 514.4444444

Example: 10 knots = 5,144.444444 millimeters per second.

About these units

Knot (kn)

NauticalCurrent unit

One nautical mile per hour, exactly 1.852 km/h. The unit of speed for ships, aircraft and wind.

Knots in a rope really were counted. Before the mid-nineteenth century, sailors threw a weighted wooden board, the chip, off the stern on a line called the log-line. The line carried knots at regular intervals, and a sailor counted how many passed through his fingers while another timed the run with a sandglass. William Bourne's A Regiment for the Sea, printed in 1574, is the first known description, and many ships spaced knots 8 fathoms, about 14.6 meters, apart with a glass of roughly half a minute.

Today a knot is one nautical mile per hour, exactly 1,852 meters per hour, about 1.151 mph or 0.514 m/s. A ship making 1 knot along a meridian covers about one minute of latitude per hour, which is why charts and the unit fit together. It is not an SI unit, and the symbol is kn, though kt is common in aviation. Saying knots per hour is wrong, since that would describe acceleration. The US moved civil aircraft standards to nautical miles and knots in 1969, and winds and currents are also quoted in them.

1 knot = 0.5144444444 meters per second (approximately).

Sources: Wikipedia: Knot (unit); Wikipedia: Chip log; NIST Guide to the SI, Appendix B.8: conversion factors

Millimeter Per Second (mm/s)

Metric (SI)Current unit

One thousandth of a meter per second. Used for very slow motion.

Biology and glaciology supply good yardsticks for a millimeter per second. The fastest-swimming bacterium, Thiovulum majus, typically moves at about 0.6 mm/s, and the Jakobshavn Isbrae glacier was recorded flowing at about 0.4 mm/s in 2003. At that rate ice covers roughly 35 meters in a day, because 0.4 mm/s multiplied by 86,400 seconds is about 34.6 m.

Faster, but still slow, is the world record speed of a snail, set in the United Kingdom at 2.75 mm/s, which works out to about 9.9 meters per hour. A millimeter per second is 0.001 m/s, so one meter per second equals 1,000 mm/s. The unit suits slow mechanisms, where meters per second would give awkward decimals, and it sits one step below the centimeter per second in the metric ladder.

1 millimeter per second = 0.001 meters per second (exactly).

Sources: Wikipedia: Orders of magnitude (speed); Wikipedia: Metre per second

Related conversions

See all speed units.