A
cubic metre per second (
m3·s-1,
m3/s,
cumecs or
cubic meter per second in American English) is a derived
SI unit of
volumetric flow rate equal to that of a
stere or
cube with sides of one
metre (~39.37
in) in
length exchanged or moving each
second. It is popularly used for water flow, especially in
rivers and
streams, and fractions for
HVAC values measuring air flow.