How to Calculate M3

Updated March 23, 2017

Cubic meters are a standard unit of volume in the metric system. A cubic meter can be visualised as a box exactly one meter in width, depth, and height. The measurement is frequently written m^3, or m with a superscript 3, to indicate a meter cubed in the same way that exponents are written with superscripts for numbers or algebraic variables. Converting between other measurements and cubic meters can be done by multiplying or dividing by conversion constants.

Convert from other metric measurements to cubic meters by dividing a meter by the other measure, then multiplying the result by itself three times. There are 100 centimetres in a meter, so there are 100 * 100 * 100, or 1,000,000 cubic centimetres in a cubic meter. Alternately, a cubic centimetre is 0.000001 cubic meters.

Convert from standard U.S. measurements with the same method, by first converting the measure into meters. One foot is 0.305 meters, so one cubic foot is 0.305 * 0.305 * 0.305, or approximately 0.028 cubic meters. ("Approximately" due to rounding error: one cubic foot is, more precisely, 0.0283168466 cubic meters.)

Convert more obscure U.S. measurements by first converting to feet, then to cubic meters. For example, it is common to measure water in acre-feet, which is one foot of water over an entire acre. An acre is 43,560 square feet, which if covered with one foot of water, would be 43,560 cubic feet of water. This calculates to 1,233.48 cubic meters.

Convert from litres to cubic meters by dividing by 1,000; a litre is defined as 1/1,000th of a cubic meter. One gallon is 3.785 litres, so convert gallons to litres by multiplying by 3.785, then divide by 1,000 for cubic meters.


Conversion values are rounded above. More precisely, one foot is 0.3048 meters; one gallon is 3.78541178 litres.

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About the Author

Ellis Davidson has been a self-employed Internet and technology consultant, entrepreneur and author since 1993. He has written a book about self-employment for recent college graduates and is a regular contributor to "Macworld" and the TidBITS technology newsletter. He is completing a book on self-employment options during a recession. Davidson holds a Bachelor of Arts in American civilization from the University of Pennsylvania.