Concrete calculator
Calculate cubic yards, number of bags, and estimated cost for slabs, footings, and columns.
in
10.0 ftin
10.0 ftin
Typical: 4"$/yd
Slab
Cubic yards
1.23
33.3 cu ft
60 lb bags
75
0.45 cu ft each
80 lb bags
56
0.6 cu ft each
Est. cost
$173
@ $140/yard
Cubic feet
33.33
57600 cu in
How Much Concrete Do I Need?
Concrete is ordered in cubic yards. One cubic yard equals 27 cubic feet and covers about 80 square feet at 4 inches thick. For small projects, premixed bags are more practical — a 60 lb bag yields about 0.45 cubic feet, and an 80 lb bag yields about 0.6 cubic feet.
Tips
- Order 5-10% extra to account for waste, uneven subgrade, and form irregularities
- Standard slab thickness is 4" for patios and walkways, 6" for driveways
- Footings are typically 8-12" deep and twice the width of the wall they support
- Sonotube columns are common at 8", 10", and 12" diameters
How many bags of concrete do I need for a 10x10 slab?
A 10'x10' slab at 4" thick requires about 1.24 cubic yards or approximately 56 bags of 60 lb mix. At 6" thick, you'd need about 1.85 cubic yards or 83 bags.
These calculators are provided for estimation and educational purposes only. Not a substitute for professional engineering judgment.