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How Many Bags of Concrete Are in a Cubic Yard?

Forty-five bags is a very different day from one phone call to the plant.

Short answer

A cubic yard takes 45 bags of 80 lb concrete, 60 bags of 60 lb, 72 bags of 50 lb, or 90 bags of 40 lb. The figure comes from the yield printed on the bag, not the weight: an 80 lb bag makes 0.60 cubic feet and there are 27 cubic feet in a yard. At retail, 45 bags runs $225–360 against $140–200 for ready-mix delivered — before the short-load fee.

Run it on your own numbers

Concrete needed
2.72 yd³
Cost
$500 – $800

Measure these

For a round column this is the diameter.

4 in residential slab, 5–6 in driveway, 6 in+ for heavy vehicles.

Sensible defaults are already applied — open only if you need to change them.

4″20′10′VOLUME · LENGTH × WIDTH × DEPTH
Concrete needed
2.72 yd³
2.47 yd³ measured + 10% · 66.7 ft³
Material cost
$500 – $800
Bags of 80 lb
123

each yields 0.6 ft³ · 2.73 yd³ equivalent

Order this much
2.75 yd³

Plants sell in quarter-yard increments

Placed weight
5.5 tons

≈ 4,050 lb per yd³

Bagged cost
$800

123 bags — compare against the truck price below

Ready-mix $140–200/yd³ plus short-load fee, or bags at retail. The lower of the two is shown as the floor.

At 2.72 yd³ you are a short load. Plants charge a surcharge under 8–10 yd³ — usually $100–200 — so budget for it and ask what their minimum is before you book.

123 bags is roughly 2.7 yards mixed by hand. Past about half a yard a truck is cheaper and vastly faster — and hand-mixing a slab in batches risks a cold joint through the middle of it.

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Bags per cubic yard by bag size

BagYieldBags per yd³Bags per ½ yd³Retail cost per yd³
80 lbcommon0.60 ft³4523$225–360
60 lb0.45 ft³6030$240–390
50 lb0.375 ft³7236$250–400
40 lb0.30 ft³9045$270–450

Bigger bags are cheaper per cubic foot every time. The only reason to buy 40 lb bags is if you cannot lift 80.

Why bag weight does not tell you the volume

The intuitive move is to divide the bag weight by concrete density — 80 lb ÷ 150 lb per cubic foot = 0.53 cubic feet. That is wrong, and it under-counts by about 12%.

The reason is water. An 80 lb bag needs roughly 6 pints of water, and that water becomes part of the finished volume. The manufacturer yield of 0.60 cubic feet already accounts for it. Use the printed yield, never a density calculation.

The same trap catches people converting the other way. Forty-five 80 lb bags is 3,600 lb of dry mix, but the placed yard weighs about 4,050 lb — the difference is the water you added.

Bags or a truck?

The crossover is around half a cubic yard. Below that, bags are cheaper and there is no minimum-load problem. Above it, ready-mix is cheaper per yard and better concrete.

The quality argument matters more than the price one. Forty-five bags cannot be mixed at once, so you are placing a slab in batches, and every batch boundary is a potential cold joint — a plane of weakness that will show. One truck is one continuous pour.

Watch the short-load surcharge, though. Most plants add $100–200 under 8–10 yards, so a single-yard delivery can land near $300. For 1–2 yards the honest comparison is bags against roughly $300, not against $170.

Frequently asked questions

How many 80 lb bags of concrete make a yard?

45. Each yields 0.60 cubic feet and a cubic yard is 27 cubic feet.

How many 60 lb bags of concrete are in a yard?

60 bags, at 0.45 cubic feet of yield each.

How many bags of concrete do I need for a 10x10 slab?

A 10 × 10 ft slab at 4 inches is 33.3 cubic feet, or 1.23 cubic yards. With 10% overage that is 61 bags of 80 lb — which is comfortably past the point where a truck makes more sense.

Why does the bag say 0.60 cubic feet when 80 lb ÷ 150 lb/ft³ is 0.53?

Because you add about 6 pints of water, and that water becomes part of the cured volume. Always use the yield printed on the bag.