Concrete Calculator
Estimate the volume of concrete for a rectangular slab in cubic yards, and how many 80 lb bags of concrete mix that works out to.
- Volume
- 33.33 cu ft
- Concrete needed
- 1.23 cu yd
- 80 lb bags to buy
- 56 bags
How this is calculated
Volume = length (ft) × width (ft) × thickness (in) ÷ 12, in cubic feet. Cubic yards = volume ÷ 27. 80 lb bags = volume ÷ 0.6 cu ft per bag, rounded up.
Assumptions
- One 80 lb bag of concrete mix yields about 0.6 cu ft.
- Bags are rounded up to whole bags.
- No allowance is added for spillage or uneven subgrade.