Concrete Calculator
Use this free concrete calculator to estimate the amount of concrete needed for your project. Select your shape, enter dimensions, and get results in cubic yards and number of bags.
How to Use This Calculator
- 1
Select your shape
Choose slab, footing, or column based on your project type.
- 2
Enter dimensions
Input the length, width, and depth (or diameter and height for columns).
- 3
Choose waste factor
Select 10% for standard projects or 15% for complex pours.
- 4
Review results
See cubic yards needed and bag counts for 60-lb and 80-lb bags.
Frequently Asked Questions
The number of bags depends on the volume of your project. A 60-lb bag of concrete yields about 0.45 cubic feet, while an 80-lb bag yields about 0.6 cubic feet. Our calculator automatically converts your dimensions to the right bag count.
One cubic yard of concrete covers 81 square feet at 4 inches thick, 54 square feet at 6 inches thick, or 27 square feet at 12 inches thick.
Yes, it is recommended to order 10% extra concrete to account for spillage, uneven subgrade, and form variations. For complex pours, consider 15% extra.
For projects requiring more than 1 cubic yard, ready-mix delivery is typically more cost-effective and practical. Bags are ideal for small repairs and projects under 1 cubic yard.