Concrete Calculator
Estimate how much ready-mix concrete you need for a rectangular slab, pad, floor or small foundation. Enter the length, width and thickness, add a sensible waste allowance, and optionally enter your local price.
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How the concrete calculator works
Estimate how much ready-mix concrete you need for a rectangular slab, pad, floor or small foundation. Enter the length, width and thickness, add a sensible waste allowance, and optionally enter your local price.
Concrete volume = length × width × thickness. The waste allowance is added after the base volume is calculated. The calculator is designed to give a useful first-pass material estimate while keeping the assumptions visible. For a purchase, compare the result with the product packaging or supplier quotation.
Common search terms for this tool include concrete calculator, concrete volume calculator, how much concrete do I need, concrete cost calculator. The wording is included naturally so the page answers the same questions people ask when planning a project.
Frequently asked questions
How much concrete do I need?
Measure the pour area and thickness, calculate length × width × thickness, then add a small waste allowance for spillage, uneven ground and delivery variation.
Should I add concrete waste?
A practical estimate often includes a small allowance, especially when the base is not perfectly level. Choose the percentage in the calculator rather than guessing from the final number.
Does this work in cubic yards?
Yes. Select imperial units to enter feet and inches; the result also shows cubic yards.
Is this a structural engineering calculator?
No. It is a material estimating tool. Structural dimensions, reinforcement and concrete specifications should be checked against local plans or a qualified professional.