Mass flow rate

Mass flow rate
Common symbols	${\displaystyle {\dot {m}}}$
SI unit	kg/s
Dimension	${\displaystyle {\mathsf {MT^{-1}}}}$

In physics and engineering, mass flow rate is the rate at which mass of a substance changes over time. Its unit is kilogram per second (kg/s) in SI units, and slug per second or pound per second in US customary units. The common symbol is ${\displaystyle {\dot {m}}}$ (pronounced "m-dot"), although sometimes ${\displaystyle \mu }$ (Greek lowercase mu) is used.

Sometimes, mass flow rate as defined here is termed "mass flux" or "mass current". Confusingly, "mass flow" is also a term for mass flux, the rate of mass flow per unit of area.