Pouring a slab for your foundation, driveway or sidewalk starts with estimating the amount of concrete you will need for the job. Estimating the number of square feet your project will cover is usually easy but meaningless when you discover that concrete is sold by the cubic yard. You can make the conversion yourself and save the time and aggravation of a professional estimate if you grab a calculator.

### Things You'll Need

- Measuring tape

- Calculator

Measure the surface area of your project.

Determine the depth of your slab.

First calculate the total square feet. For a 30X50-foot slab, multiply 30 by 50 to get 1,500 square feet.

Multiply the depth of the slab by the square footage. Continuing the example above, for a 6-inch slab, multiply 1500 by 0.5 to get 750 cubic feet.

To get cubic yards, divide your answer by 27 (the number of cubic feet in a cubic yard). For our example: divide 750 by 27 to get 27.7.