Concrete Volume Calculator
Estimate slab or round-column concrete volume and rounded-up bags from an editable bag yield.
Method checked 2026-09-15 · Methods & sources · Examples are estimates, not current offers or quotes.
Your estimate
Fill in the inputs and select Calculate. Results clear when you change an input so you can compare a fresh estimate.
How this calculator works
For a slab, volume is length times width times thickness after converting inches to feet. For a round column, volume is π times radius squared times height.
The selected waste percentage is applied after the geometric volume. Results are shown in cubic feet, cubic yards, and cubic meters for comparison.
Bag count divides the waste-adjusted volume by the yield entered from the product information and rounds up. Mix design, reinforcement, loads, and required dimensions are outside this calculator.
Worked example
For the slab option, 10 ft × 12 ft × 4 in equals 40.00 cu ft, or 1.481 cu yd, before waste. With a 0.60 cu ft entered yield, it rounds to 67 bags before waste.
Common questions
Why do I enter bag yield?
Yields differ by mix and bag size. Use the yield stated for the product you are purchasing rather than assuming one bag size.
Can this size a structural slab or column?
No. It estimates quantity only. Structural requirements depend on loads, soil, reinforcement, code, and project conditions.