Concrete Volume (Slab) Calculator

Calculate the volume of concrete needed for a rectangular slab, patio, or driveway. Enter length, width, and thickness to get cubic yards and bags needed.

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Concrete is sold by the cubic yard. One cubic yard equals 27 cubic feet. For slabs, standard thickness is 4 inches for patios and walkways, 6 inches for driveways. Always add 5-10% for waste due to uneven subgrade, spillage, and form imperfections. For anything over 1 cubic yard, ordering ready-mix from a truck is usually more economical than bags.