How to Calculate Concrete Footer Volume

Pouring a Footing

When you are pouring concrete footings, you must be able to calculate how much concrete you'll need so you do not run out after you have started pouring. The average concrete footing is 8 inches deep and twice as wide as the width of the wall it will support. However, since concrete is ordered in cubic yards rather than cubic feet, you must convert the numbers before you place your order. Follow the steps below to learn how to correctly measure and convert the amount of concrete you need.

Things You'll Need

• Tape measure
• Calculator

Instructions

1. Measure the length, width and depth in feet of all your footings.

2. Multiply the length by the width and the depth. For example, multiply 90 feet long by 2 feet wide by .66 feet deep to get 119 cubic feet.

3. Divide the answer by 27 to convert into cubic yards. Using the above example, 119 divided by 27 equals 4.4 cubic yards.

4. Increase the total by 5 percent to ensure that you do not run short. In our example, 4.40 multiplied by 1.05 equals 4.6 cubic yards of concrete.

5. Prepare a place to put any leftover concrete and drive some steel rods 8 inches high along the middle of your footings to help you level the concrete after you pour it.