Millimeter Per Second (mm/s)

Metric (SI)Current unit

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

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

About the millimeter per second

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.

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

Millimeter Per Second conversion chart

1 millimeter per second expressed in every other speed unit:

More Metric (SI) units

• meter per second (speed)
• kilometer per hour (speed)
• centimeter per second (speed)
• kilometer per minute (speed)
• meter per minute (speed)
• meter (length)
• kilometer (length)
• centimeter (length)
• millimeter (length)
• micrometer (length)
• nanometer (length)
• picometer (length)
• decimeter (length)
• hectometer (length)
• decameter (length)
• kilogram (weight & mass)

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