Estimate the volume, weight, and number of bags of concrete needed for a slab, footing, wall, or hole.
Volume is simply length × width × thickness for slabs, or πr² × depth for a round hole or column. This calculator assumes a standard pre-mixed concrete density of 133 lbs per cubic foot (2,130 kg/m³) to convert that volume into a weight, and then into bag counts.
Real-world pours rarely come out to an exact volume — uneven ground, formwork gaps, and spillage all eat into your supply. Contractors commonly buy 5–10% more concrete than the calculated volume to avoid running short mid-pour.
That's a typical density for standard pre-mixed concrete, but it varies by product — check your bag's label for an exact figure if precision matters.
Yes — each dimension has its own unit selector, so you can enter thickness in inches while length and width stay in feet, matching how these projects are usually measured.
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