Convert between different units quickly and accurately in a modern way
Choose a Measurement
Select a measurement and convert between different units
Multiple conversions
To convert from Millimeter per hour (mm/h) to Meter per second (m/s), use the following formula:
To convert from Millimeter per hour (mm/h) to Kilometer per hour (km/h), use the following formula:
To convert from Millimeter per hour (mm/h) to Mile per hour (mph), use the following formula:
With is the ratio between the base units Mile per hour (mph) and Kilometer per hour (km/h).
To convert from Millimeter per hour (mm/h) to Knot (knot), use the following formula:
With is the ratio between the base units Mile per hour (mph) and Kilometer per hour (km/h).
To convert from Millimeter per hour (mm/h) to Foot per second (ft/s), use the following formula:
With is the ratio between the base units Mile per hour (mph) and Kilometer per hour (km/h).
To convert from Millimeter per hour (mm/h) to Foot per minute (ft/min), use the following formula:
With is the ratio between the base units Mile per hour (mph) and Kilometer per hour (km/h).
To convert from Millimeter per hour (mm/h) to Inch per hour (in/h), use the following formula:
With is the ratio between the base units Mile per hour (mph) and Kilometer per hour (km/h).
A millimeter per hour (mm/h) is a metric unit for measuring extremely slow speeds.
To put it in perspective, it equals just one-millionth of a kilometer per hour.
In meteorology, precipitation intensity is usually given in millimeters per hour (mm/h).
That number tells you how deep the water would be on a flat surface after an hour if it didn't drain or evaporate.
Weather services use these thresholds to classify rainfall:
The use of mm/h ensures that weather reports are uniform and readily comprehensible globally.
Aside from meteorological predictions, mm/h is an essential unit in hydrology and agriculture for quantifying rates of evaporation and infiltration.
Scientists use it to quantify how quickly water evaporates from lakes and reservoirs or how fast it soaks into the soil.
This information is crucial for:
Millimeters per hour (mm/h) is a handy unit for describing speeds so slow the human eye barely notices. It covers much smaller motion—from microscopic growth to geological creep.
For example, a garden snail moves at roughly 3,600 mm per hour (about 1 mm/second).
Scientists use mm/h to measure slow processes, such as:
This makes it a key unit across many scientific fields.