Material calculator
Concrete Calculator
Estimate the concrete needed for slabs, footings, and post holes, shown in cubic yards, cubic meters, or bags.
How to use this calculator
Choose a rectangular section or a round hole, enter its dimensions, and add the number of same-size sections. Select ready-mix or bagged concrete. For bags, enter the yield printed on the product label.
Enter an optional price per cubic yard for ready-mix concrete or price per bag for bagged concrete to estimate material cost.
How the estimate is calculated
Rectangular concrete uses length × width × depth. A round hole uses π × radius² × depth. The calculator multiplies repeated sections, adds the waste percentage you choose, converts the result to the selected purchase unit, and rounds full bags up before calculating cost.
Example
A 10 ft × 12 ft slab at 4 in deep has a volume of 40 cu ft, or about 1.48 cu yd. At 0.60 cu ft per bag, it requires 67 full bags before any additional waste is selected.
Before you buy
Confirm the finished dimensions and the yield on the concrete label. This calculator estimates volume only; it does not determine mix design, strength, reinforcement, footing design, or code compliance.
Check local requirements for structural or permitted work.
Frequently asked questions
Why are bags rounded up?
Partial bags are not a practical purchase unit, so the calculator rounds the final bag count to the next whole bag.
Does this calculate stairs?
No. This calculator covers rectangular sections and cylindrical post holes. Stairs require a different calculation.
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