How to calculate cubic feet ? - Building Materials

The above was very good,very simply it is length x wide x depth divided by 27 equels cubic feet

As previously posted, cubic feet is Length (in feet) X Width (in feet) X Height (in feet).

But a frequent "head scratcher" arises when one of the dimensions is in inches. To get cubic feet when one of your 3 dimensions is in inches, for that measurement take 1 divided by 12 (0.083) and multiply that by the number of inches.

1" = .083 feet
2" = .16 feet
3" = .25 feet
4" = .33 feet
5" = .42 feet
6" = .50 feet, and so on and so forth...

Example: You have a concrete slab that is 10 foot wide x 20 foot long x 5 inches thick. Cubic feet will be 10' x 20' x 0.42 = 84 cubic feet.
(Note: the 0.42 figure is the conversion of 5" into feet), which is (0.083 x 5). Hope this helps.

Now... to convert cubic feet into cubic yards (for things like concrete) you would take the cubic feet (84 in this example) and divide that by 27. (One cubic yard = 27 cubic feet).
So 84 cubic feet will be 3.11 cubic yds.

Calculating the cubic feet of a space requires multiplying the area of the bottom times the average height. You get the bottom area by multiplying the length times the width. Remember, to get cubic feet, you need all your measurements in feet to start with.

Here is your formula:

VOLUME (in cubic feet) = Length (in feet) X Width (in feet) X Height (in feet)

If it's a rectangular room you're working with, it is all straightforward. If there are irregular walls, it may be necessary to divide up the room into rectangular sections and then add together their individual volumes. If the ceiling is sloped, you need to use the height that has the same ceiling area above it as below it. Good luck! Truly.