Concrete Calculator
Enter your slab's length, width, and thickness to see exactly how much concrete to order — in cubic yards with 10% waste included, plus bag counts for smaller pours.
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Cubic yards (incl. 10% waste)
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How much concrete do I need?
Concrete is sold by the cubic yard (27 cubic feet). Multiply your slab's length and width in feet by its thickness converted to feet, then divide by 27. The hero number already includes 10% extra for uneven subgrade, spillage, and slight over-digging — order that amount. For small jobs, an 80 lb bag yields about 0.6 ft³ and a 60 lb bag about 0.45 ft³; over roughly a yard, ready-mix delivery is usually cheaper than bags.