Concrete Volume Calculator
Cubic yards (and bag count) for slabs, footings, and columns.
Pick a pour type (slab, footing, column), enter dimensions, get cubic yards needed plus equivalent in 60-lb and 80-lb bags.
Shape
Why concrete is measured in cubic yards
Ready-mix concrete (from a truck) is sold by the cubic yard (27 cubic feet). Bagged concrete is sold by the bag, with each 60-lb bag yielding about 0.45 cubic feet of concrete and each 80-lb bag yielding about 0.6 cubic feet. This calculator gives you both so you can compare costs.
Always add waste cushion
This calculator suggests 10 percent waste, which is the standard cushion for residential pours. Reasons to add cushion: uneven ground means deeper pours in some spots, spillage during pouring, slight over-ordering being cheaper than running short mid-pour. For complex pours (multiple levels, lots of forming), bump to 15 percent.
Truck vs bags
- Under 1 cubic yard: bags are cheaper and easier (no truck delivery fee)
- 1-3 cubic yards: either works; trucks have minimum-load fees that can make bags competitive
- 3+ cubic yards: truck almost always cheaper, and you avoid mixing 100+ bags by hand
Typical ready-mix prices are $125-200 per cubic yard delivered (varies by region and trip distance), with minimum charges around $300-500 per delivery. A 60-lb bag costs $4-7 retail, an 80-lb bag costs $6-10. Run the math for your project before deciding.
What to know about thickness
- Sidewalks, patios: 4 inches typical
- Driveways: 4 inches for cars, 5-6 inches for trucks or heavy vehicles
- Foundations / basement floors: 4-6 inches with rebar
- Footings: follow local code (typically 12 inches deep, 16-24 inches wide)