Find your total volume yield and exact bag counts instantly.
To find the concrete volume needed for a rectangular slab, multiply length by width to find the square footage, convert your thickness from inches to feet (divide by 12), multiply them all together to get cubic feet, and finally divide by 27 to yield cubic yards.
Accurately estimating concrete for a slab pour requires balancing dimensional volume math against real-world job site variables. While geometry provides a baseline, actual pouring involves factoring in sub-grade settlement, ground level variations, and material spillage. Relying strictly on exact dimensions without accounting for layout fluctuations frequently leads to under-ordering, causing catastrophic mid-pour cold joints.
To manually calculate cubic yards: Multiply Length (ft) × Width (ft) × Thickness (in / 12) to get total cubic feet. Divide that number by 27 to find the true cubic yards. For pre-mixed commercial bags, multiply your total cubic yards by the specific yields listed below.
Industry professionals universally append a 5% to 10% safety buffer to their concrete orders. This structural buffer safely accommodates minor grade excavations, baseline shifts, and mixing waste inside the hopper.
| Bag Size Profile | Yield Per Single Bag | Bags Needed Per Cubic Yard |
|---|---|---|
| 80 lb Concrete Mix Bag | 0.60 Cubic Feet | 45 Bags |
| 60 lb Concrete Mix Bag | 0.45 Cubic Feet | 60 Bags |