Concrete Bag Yield
concrete
The volume of finished concrete a single bag of mix produces — about 0.60 cubic feet for an 80-lb bag, 0.45 for a 60-lb, and 0.30 for a 40-lb.
Yield is what converts a volume estimate into a shopping list. It takes 45 eighty-pound bags to make one cubic yard, which is roughly 3,600 lb of material to carry, mix, and place before it starts setting. That number is the practical dividing line between bagged and ready-mix: below about half a cubic yard bagged is more convenient, above it ready-mix is cheaper per yard and dramatically less work. Mixing a large pour by hand also risks cold joints, since a batch that sets before the next is placed leaves a permanent plane of weakness.
Formula
Bags = total volume ft³ ÷ bag yield ft³
Example
A 1.23 yd³ slab is 33.3 ft³. At 0.60 ft³ per 80-lb bag, that is 56 bags — about 4,480 lb of concrete mix.
Common mistake
Assuming an 80-lb bag yields 80 lb worth of anything useful. The yield is a volume, not a weight, and the water you add changes the weight but not the volume it fills.
Use the Concrete Calculator
Calculate cubic yards, cubic meters, and the number of 40, 60, and 80-lb concrete bags for slabs, footings, and columns. Optional price input gives a full project cost.
Open Concrete Calculator →Related Terms
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