Cubic metre per second

A cubic metre per second (m³s⁻¹, m³/s, cumecs or cubic meter per second in American English) is the unit of volumetric flow rate in the International System of Units (SI) 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.

Cubic metre per second
Unit system	SI
Unit of	volumetric flow rate
Symbol	m^3/s
In SI base units	m^3·s^−1

The term cumec is also used, as shorthand for "Cubic metres per second",^[1] with the plural form cumecs also common in speech.^{[citation needed]} It is commonly used between workers in the measurement of water flow through natural streams and civil works, but rarely used in writing. Data in units of cumec are used along the y-axis or vertical axis of a flow hydrograph, which describes the time variation of discharge of a river (the mean velocity multiplied by cross-sectional area). A moderately sized river discharges in the order of 100 cumecs.

Conversions

1 cubic metre per second	=	1000	litres per second
	=	60	kilolitres per minute
	=	86.4	megalitres per day
	=	31.5576	gigalitres per year
	≈	219.969248	imperial gallons per second
	≈	264.172051	US gallons per second
	≈	35.314454	cubic feet per second
	≈	1.305	cubic yards per second
	≈	25566.497	acre-feet per year
	≈	1113676621	cubic feet per year
	≈	0.00757090916	cubic miles per year

References

1. "Units: C", The University of North Carolina at Chapel Hill, webpage: UNC-Rowlett. on June 2, 2018.

See also

• Standard litre per minute
• Conversion of units
• Volumetric flow rate
• Volumetric flux
• Cusec, shorthand for cubic feet per second