Concrete bags

Choose based on how much weight you want to carry and how many bags you are willing to handle. The 60 lb bag is lighter to lift, while the 80 lb bag yields 0.6 cu ft per bag versus 0.45 cu ft for the 60 lb bag, so for the same slab you will need fewer 80 lb bags. Both counts are shown after you enter your dimensions.

The reference price shown on this page comes from one retailer's listing and is for the 80 lb bag only, checked Sep 2026. The 60 lb bag count is shown without a cost line because no reference price has been provided for that size.

A 10% waste factor is added to the calculated slab volume before the bag count is determined. The extra material covers spills, uneven ground, and off-cuts, and it is applied equally to the 60 lb and 80 lb counts.

For a 10 by 10 foot slab poured 4 inches thick, you need 82 bags of 60 lb concrete mix. That count includes the 10% overage for spillage and uneven ground. The same slab takes 62 bags of 80 lb mix if you prefer fewer, heavier bags.

The cheaper option depends on the size of the pour. Bagged concrete suits small jobs because you buy only what you use. Ready mix is ordered by the cubic yard and often has delivery minimums, so at around a cubic yard and up it is worth getting a ready mix quote. A cubic yard is about 45 bags of 80 lb mix or 60 bags of 60 lb mix.

A cubic yard of concrete takes about 45 bags of 80 lb mix, or about 60 bags of 60 lb mix. That is the amount before adding the waste allowance. For a slab, you will typically need about 10% more than that to cover waste.