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Calculate concrete volume, cubic yards, bags, and cost for slabs, pads, footings, and blocks. Free concrete material calculator with a waste factor.
Grounded in available product and source data
Estimate includes your waste factor. Figures are estimates, not a quote.
Rectangular pours use volume = length × width × thickness, converted to cubic yards by dividing cubic feet by 27. Post holes use π × radius² × depth. Bag counts always round up.
= ≈ 1.36 cubic yards, or 62 × 80 lb bags
Start with this general calculator when you only know the shape. Use a dedicated calculator when your buying decision depends on bags, blocks, or post holes.
All tools use planning estimates; structural design, reinforcement, and code compliance remain local/project-specific.
Multiply length × width × thickness (in feet) to get cubic feet, then divide by 27 for cubic yards. Add a waste factor of about 10% so you do not run short. This calculator does all of that for you and also shows the number of bags.
It depends on the bag size. An 80 lb bag yields about 0.60 cubic feet, a 60 lb bag about 0.45, a 50 lb bag about 0.375, and a 40 lb bag about 0.30. Divide your waste-adjusted volume by the yield and round up. The bag comparison shows all four sizes at once.
One cubic yard equals 27 cubic feet. Ready-mix prices vary a lot by region and supplier, so enter your local price per cubic yard to get an estimate — this tool does not assume a national price.
