Concrete for a 8 × 8 slab
Short answer
A 8 × 8 ft slab at 4" thick needs about 0.79 cubic yards of concrete — roughly 40 80-lb or 53 60-lb pre-mix bags (including 10% waste).
Concrete
0.79 yd³
80-lb bags
40
60-lb bags
53
40-lb bags
79
8 × 8 slab at 4" thick
A 8 × 8 ft slab is 64 square feet. At the standard 4-inch thickness that works out to 21.3 cubic feet, or 0.79 cubic yards including a 10% waste allowance. For a driveway or anything bearing vehicle loads, step up to 5–6 inches.
Different size or thickness?
Open the concrete calculatorOther slab sizes
Frequently asked questions
How much concrete for a 8 × 8 slab?
A 8 × 8 ft slab at 4" thick needs about 0.79 cubic yards (21.3 cubic feet), including a 10% waste allowance.
How many bags of concrete for a 8 × 8 slab?
About 40 80-lb bags, 53 60-lb bags, or 79 40-lb bags. Above roughly 1 cubic yard it is usually cheaper to order ready-mix than to buy bags.
Is a 4-inch slab thick enough?
Four inches is standard for patios, walkways, and shed floors. Go to 5–6 inches for driveways or anything carrying vehicle loads. Change the thickness in the calculator to see the new amount.