Concrete Bag Calculator

A 40 lb bag yields about 0.30 cubic feet of mixed concrete, a 60 lb bag yields 0.45, an 80 lb bag yields 0.60, and a 90 lb bag yields 0.675. The calculator divides your pour volume by the selected yield, applies your waste percentage, then rounds up to whole bags. Check the yield printed on the product you buy.

60 lb and 80 lb bags are common for residential pours. Use 40 lb bags when handling weight matters. A 90 lb bag yields more concrete but is harder to move. One cubic yard takes 45 bags of 80 lb mix before waste, so compare ready-mix delivery once your project approaches that size.

Some concrete spills off the mixer, sticks to tools, or gets thrown away because the mix went off in the wheelbarrow. The default 10% waste catches all of that and the inevitable miscalculation in pour depth. Drop it to 5% for clean, simple slabs or push it to 15% for footings with uneven subgrade or many small pours.

The calculator multiplies the final bag count (with waste) by the bag weight, so 62 bags of 80 lb mix come out to 4,960 lb of dry product. That figure helps you plan delivery, decide if a pallet jack or two-person carry is enough, and confirm your truck or trailer can handle the load.

About 1 cubic yard is the break-even point. At that volume you would need roughly 45 bags of 80 lb mix, which costs about as much as the smallest ready-mix delivery and takes far more time and mixing equipment. Above 2 cubic yards, ready-mix wins on both cost and consistency, since one truck delivers the entire pour in a uniform mix.