How Many Bags of Concrete in a Cubic Yard?

One cubic yard of concrete is 27 cubic feet. To find how many bags that takes, divide 27 by the bag's yield — the volume of mixed concrete one bag produces. Because yield rises with bag weight, bigger bags mean fewer of them, which is why the answer depends entirely on the size you buy.

So a single cubic yard is about 45 eighty-pound bags — and that's the catch most people miss. Forty-five 80-lb bags is over 3,600 lb of material to buy, haul, open, and mix by hand, one bag at a time. The weight and labor are exactly why pours past a yard usually go to a ready-mix truck.

Coverage per bag

If you're thinking in area rather than volume, an 80-lb bag covers about 1.8 square feet at 4 inches thick (or 3.6 sq ft at 2 inches). A 60-lb bag covers about three-quarters of that. For a small pad you can work backward: a 3 × 3 ft, 4-inch pad is 3 cubic feet, which is five 80-lb bags or about seven 60-lb bags.

Always buy a few extra

Add 5–10% to your bag count for spillage, a slightly deeper-than-planned pour, and the odd bag that's gone hard in storage. Unopened bags can usually be returned, so erring high is cheap insurance against running short with wet concrete already in the forms.

When to stop counting bags

Bagged mix is ideal for small, separate pours — post holes, a shed pad, steps, a short walkway, repairs. Once the count climbs past 20–30 bags, the hauling and mixing become the real cost, not the concrete. At that point price a ready-mix truck instead; see the bags-vs-ready-mix calculator for the crossover at your volume. For an exact bag count for any project, every calculator on the site shows 60- and 80-lb counts automatically, and the bag calculator works from a volume you already have.