Things You'll Need
Concrete is a necessary item for many home improvement projects. Whether you're pouring a driveway or a pool deck, one of the first things you'll need to know is how much concrete you're going to need to complete the job. In order to figure square feet for a concrete project, you only need to perform a few simple calculations.
Measure the length and width of the area you plan to pour concrete over.
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Multiply the length times the width for square footage. For instance, if you plan to pour a concrete driveway that will be 25 feet long and 12 feet wide, the square footage would be 300 square feet.
Measure all the sides for an area that isn't shaped like a rectangle or square.
Draw a scale drawing of the area on graph paper.
Section the drawing into rectangles, squares and triangles.
Find the area of each section. For squares and rectangles, multiply length times width. For triangles, multiply base times height and divide the product by 2.
Add the area of each section to find the total area.
Convert the thickness of your concrete into feet by dividing inches by 12. For instance, if you want your driveway to be 4 inches thick, divide 4 by 12 to get 0.333 feet of concrete.
Multiply the area by the thickness. For this example, multiply 300 times 0.333 to get 99.9 cubic feet of concrete.
Convert the cubic feet into cubic yards, since that's how concrete is usually measured. Do this by dividing by 27 (3 feet by 3 feet by 3 feet). The equation would look like this: 99.9 / 27 = 3.7 cubic yards
You would need 3.7 cubic yards to pave a 4-inch thick driveway that's 25 feet long and 12 feet wide.