Concrete Calculator
Calculate how many cubic yards of concrete you need for your project. This free concrete calculator handles rectangular slabs, footings, and circular columns or pads. Enter your dimensions below for an instant estimate.
Enter Your Measurements
Full Breakdown
Dimensions
Surface Area
Volume
Volume
Pre-mixed Bags
Pre-mixed Bags
How to Use This Calculator
- Select the shape of your pour — rectangle for slabs and footings, circle for columns and pads.
- Enter the length, width (or diameter), and depth of your project.
- Click "Calculate Concrete" to see cubic yards needed plus bag estimates.
- Order 5–10% extra to account for waste, spillage, and uneven subgrade.
The Formula
For rectangular shapes:
Cubic Yards = (Length × Width × Depth) ÷ 27
Where length and width are in feet, depth is converted from inches to feet (÷ 12), and the result in cubic feet is divided by 27 to convert to cubic yards.
For circular shapes:
Cubic Yards = (π × r² × Depth) ÷ 27
Where r is the radius in feet (diameter ÷ 2).