Concrete Mix Calculator
Calculate bags of premix concrete needed for any project. Shows bag counts for 40, 60, and 80 lb bags with waste factor.
๐๏ธ Concrete Mix Calculator
Results
Volume36.67 cu ft
Cubic Yards1.36 cu yd
40 lb Bags123 bags
60 lb Bags82 bags
80 lb Bags62 bags
๐ก How Many Bags of Concrete Do I Need?
Premix concrete bags are sold by weight. An 80 lb bag yields about 0.60 cu ft. A 60 lb bag yields 0.45 cu ft. A 40 lb bag yields 0.30 cu ft. Calculate your project volume in cubic feet (length ร width ร thickness), add 10% for waste, then divide by the yield per bag.
For projects over 1 cubic yard (27 cu ft), consider ordering ready-mix concrete from a truck โ it's cheaper per yard and much less labor. Premix bags are best for small projects: fence posts, small pads, repairs, and patching.
A 10ร10 ft slab, 4 inches thick: 33.3 cu ft. With 10% waste: 36.7 cu ft. That's 62 bags at 80 lbs โ about 2,480 lbs of bags. Consider ready-mix at this size.