How to Calculate Concrete Curbs & Gutters
- 1). Know that the formula for calculating concrete is written as the following: ((Length X Width X Height)/27) X 1.05 = Total concrete needed plus 5% extra. This formula is compatible with measurements calculated in feet. The figure of 1.05 is included because it is usually recommended that you purchase 5% more concrete than what you need to ensure you have enough concrete in the event of mishaps.
- 2). Measure the length, width and height of the trench to be filled to create the curb or gutter, and be sure to measure in feet. For instance, in this example, let's assume that the length of the curb or gutter is 100 feet, the width is 5 feet and the height is 1/3 feet.
- 3). Multiply the length times the width times the height to determine how many cubic feet of concrete you need: 100 ft X 5 ft X 1/3 ft = 166.66 cubic feet.
- 4). Divide the above product by 27 (3 cubic ft X 3 cubic ft X 3 cubic ft) to determine the number of cubic yards of concrete you need to make your curb or gutter: 166.66 cubic ft/27 cubic ft = 6.173 cubic yards. Converting the measurements to yards is essential because concrete is sold in cubic yards.
- 5). Multiply the cubic yards needed to fill the trench by 1.05 to derive the total concrete needed plus 5% extra: 6.175 X 1.05 = 6.481 cubic yards.