Concrete is sold by the cubic yard, so when you purchase concrete to fill a space, you'll have to know the cubic yardage of that space beforehand. If you already know the area of the space in square yards, you're more than halfway there. All that the cubic yardage provides is the third dimension of the space, taking into account the height of the slab you're pouring, along with the area of the space provided by the square yardage. The calculation is a simple one, once you have all of the measurements necessary. Once you've made your calculations, you can purchase enough concrete to complete your project without worry.
Measure the length and the width of the area you need to cover in concrete. Write down the measurements.
Multiply the length of the proposed concrete slab by the width of the slab to calculate the area of the slab in square yards.
Convert the square yardage to cubic yards by using the planned depth of the slab. Multiply the area of the slab by the intended slab depth. Your result represents the cubic yards of concrete needed to cover an area the width and length measured with a slab of the proposed thickness.