Concrete calculator for contractors

Get cubic yards to order, bag counts and material cost for any slab, patio, driveway or walk.

Length (ft)Width (ft)Thickness (in)4 in patios and walks, 5–6 in driveways and garagesWaste and over-pour (%)Ready-mix price per yard ($)Delivered, from your supplier

Concrete to order7.82 cu yd

Exact volume7.11 cu yd (192.0 cu ft)

Ready-mix material cost$1,290.67

Or 80 lb bags (0.6 cu ft each)352

Or 60 lb bags (0.45 cu ft each)470

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Frequently asked questions

How do you calculate cubic yards of concrete?

Multiply length × width × thickness, all in feet, then divide by 27. A 24 × 24 ft slab at 4 inches (0.333 ft) is 192 cu ft, or about 7.1 cubic yards before waste.

How much extra concrete should I order?

Most contractors add 5 to 10% for uneven subgrade, spillage and form flex. Thickened edges and footings need to be calculated separately and added.

How many bags of concrete make a yard?

About 45 bags of 80 lb mix (0.6 cu ft each) or 60 bags of 60 lb mix (0.45 cu ft each). Past a yard or so, ready-mix is usually cheaper and faster.

How thick should a concrete slab be?

Four inches is common for patios, walks and sheds. Driveways and garage floors are typically 5 to 6 inches with reinforcement.