Why use this calculator
Ordering the right amount of concrete saves money and prevents project delays. Too little means a second delivery; too much is wasted material.
How to use it
Enter the length, width (in feet) and depth (in inches) of your concrete pour. The calculator converts everything to cubic yards and estimates bag quantities.
The formula
Volume = Length × Width × (Depth/12) cubic feet. Cubic Yards = Cubic Feet / 27. Add 10% for waste in practice.
Worked examples
20' × 10' slab, 4" deep
2.47 cubic yards, about 83 bags (80-lb)
When people use it
- Driveway construction
- Patio projects
- Foundation work
- Sidewalks and pathways
Tips
- Order 10% extra for waste and spillage
- Concrete is sold by the cubic yard from ready-mix suppliers
- For small projects, bagged concrete may be more practical
- Consider rebar or wire mesh for structural integrity
Questions people ask
- How thick should concrete be?
- 4 inches is standard for walkways and patios. Driveways typically need 5-6 inches. Foundations and heavy-duty slabs may require 8+ inches. Check local building codes.