Measure the length and width of the basement floor using a tape measure. Write down the measurements.
Measure the depth of concrete you want on the basement floor. Write down the figure.
Multiply the three figures. For example, if the length is 10 feet, the width is 15 feet and the depth is 1 foot, multiply 10 by 15 by 1 to get 150. This represents the cubic feet.
Convert the figure you calculated into cubic yards. This is the measurement concrete is sold in. Do this by dividing the figure by 27; there are 27 cubic feet in a cubic yard. For example, if the figure is 150, then 150 divided by 27 equals 5.5 cubic yards.