How Much is a Cubic Yard of Concrete?

The project, a patio across the back of the house. When finished it will measure 15 feet by 30 feet. You want it to be sturdy and last so you plan to pour the concrete to a depth of 4 inches. You have your plan, but just how much concrete will it take to build this patio? To get this answer you will need to do just a few simple calculations.

The first calculation is to determine how many cubic inches are in a cubic yard. This is done by multiplying the height times the width times the depth of a cubic yard. This calculation will tell you there are 46,656 cubic inches in a cubic yard. (36 x 36 x 36 = 46,656)

The next number you will need to find is how much concrete it will take to cover a square foot of patio 4 inches deep. This is done in the same way we calculated the cubic yard. Height times width times depth. (12 x 12 x 4 = 576) For every square foot of concrete four inches deep you will need 576 cubic inches of concrete. You now have two of your four numbers needed.

The next calculation is a simple one. Take the total cubic inches in a cubic yard and divide it by the number of cubic inches needed to cover a square foot. 46,656 divided by 576 = 81 square feet covered per cubic yard. You will also need to know how many square feet you are covering. To find this number multiple the length times the width of the planned patio. 15 x 30 = 450 square feet

You now know you need to cover 450 square feet and one cubic yard of concrete will cover 81 square feet. To determine the amount of concrete required for this project divide 450 by 81. This calculation will show you need 5.55 cubic yards of concrete to complete your project. You now know exactly what to order when calling the concrete supplier.

Recap of calculation:
One cubic yard = 46,656 cubic inches (36 x 36 x 36)
Each Square foot requires 576 cubic inches (12 x 12 x 4)
One cubic yard of concrete will cover 81 square feet at a depth of 4 inches
Project covers 450 square feet (15 x 30)
Entire project will take 5.55 cubic yards of concrete (450 divided by 81)