0.00
Cubic Yards Required
*Includes 10% waste factor
0.0
Cubic Feet
0
80lb Bags
0
60lb Bags
Calculating the amount of concrete you need is a straightforward process, but accuracy is crucial to avoid running short during a pour. The formula for estimating concrete volume depends on the shape of your project.
For rectangular slabs and square footings, you multiply the length, width, and depth together. Since concrete is ordered in cubic yards, you must convert all measurements to a consistent unit (usually feet) before multiplying. The formula is: Length (ft) × Width (ft) × Depth (ft) = Cubic Feet. To get cubic yards, divide the total cubic feet by 27.
Our calculator automatically includes a 10% waste factor in the final results. This is an industry standard practice for several important reasons:
Running out of concrete halfway through a pour creates a "cold joint," which severely weakens the structural integrity of the slab. Ordering slightly more than the mathematical exact volume is the cheapest insurance you can buy against a ruined project.
When you need less than 1 to 1.5 cubic yards of concrete, mixing bags is usually the most economical choice. For larger projects, ordering a ready-mix truck is highly recommended to save time, labor, and ensure a consistent mix.
To calculate bags manually, you need to know the yield of each bag size. A standard 80lb bag of concrete mix yields approximately 0.60 cubic feet when mixed with water. A 60lb bag yields approximately 0.45 cubic feet. Divide your total required cubic feet by the bag yield to determine how many bags you need to purchase.
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