How this calculator works
The volume of a rectangular box is its length times its width times its height. When all three sides are measured in feet, the product is in cubic feet. Each input can be given in its own unit, and the calculator converts the sides to metres before multiplying, so mixing feet with inches or metres is allowed. The answer is then offered in cubic feet, cubic metres, litres, US gallons, imperial gallons and cubic inches. A cubic foot is the volume of a cube one foot on each side.
Formula
volume = length x width x height. 1 ft3 = 0.028316846592 m3 exactly, so cubic feet = cubic metres / 0.028316846592. 1 ft3 = 28.316846592 L = 7.480519 US gallons = 6.228835 imperial gallons.
Worked example
A box 3 ft by 4 ft by 5 ft has a volume of 3 x 4 x 5 = 60 ft3, which is 1.69901 m3 or 1,699.01 L. A 12 in by 12 in by 12 in cube is exactly 1 ft3. A space 2 m by 1 m by 0.5 m is 1 m3, or 35.3147 ft3.
Advertisement
Frequently asked questions
How do I convert cubic feet to cubic metres?
Multiply by 0.028316846592, because a foot is exactly 0.3048 m and 0.3048 cubed is 0.028316846592. For a quick estimate, divide cubic feet by about 35.3.
Can I mix feet and inches in one calculation?
Yes. Each side has its own unit selector. Convert a measurement such as 5 ft 6 in to 5.5 ft, or enter the inches in the inches unit, and the page handles the rest. A feet-and-inches split is not entered as two separate boxes here.
Is cubic footage the same as shipping volume?
Cubic footage measures the space a package occupies. Carriers often also apply dimensional weight, which divides the cubic size by a divisor to estimate chargeable weight. That divisor depends on the carrier and units, so it is not part of this calculation.
What if one side is zero?
The volume is zero, which is correct for a flat shape with no thickness. A negative side is rejected because a length cannot be negative.