Concrete Calculator
Estimate slabs, footings, walls, columns, circular slabs, and post holes in bags or cubic yards.
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How this calculator works
Slabs/footings use length × width × thickness. Walls use length × height × thickness. Columns and post holes use π × radius² × height; circular slabs use π × radius² × thickness. Feet + inches are converted before calculating. Divide cubic feet by 27 for cubic yards. Waste-adjusted bags round up; bulk orders round up to 0.1 yard.
Use current quotes, local rates, and measured dimensions to make this estimate useful for your situation.
Frequently asked questions
How many bags are in a cubic yard?+
Divide 27 cu ft by the printed bag yield. At 0.6 cu ft per 80 lb bag, one yard requires 45 bags before waste.
Should I add waste?+
An allowance can cover uneven excavation, forms, and handling losses. Use measured dimensions and confirm supplier minimums before ordering.