Concrete Calculator
Estimate cubic yards of concrete and bags needed for slabs, footings and round columns. Free construction calculator.
Frequently asked questions
- How much extra concrete should I order?
- 10% covers spillage, uneven grade and form movement. Complex shapes or sloped sites justify 15%.
- Why are there cubic feet and cubic yards?
- Ready-mix is ordered by the cubic yard (27 cu ft), while bagged concrete yields are listed per bag — the tool gives both.
- What thickness for a residential slab?
- 4 inches for most patios and walkways, 6 inches for driveways and areas carrying vehicle loads.
This tool runs entirely in your browser. No data is uploaded anywhere.