How we calculate
Volume = length × width × thickness, converted to cubic feet, plus a 10% allowance for uneven subgrade and spillage. One cubic yard = 27 cubic feet. An 80-lb bag yields about 0.6 cu ft of concrete, a 60-lb bag about 0.45 cu ft. Driveways are typically 4 inches thick (5–6 where heavy vehicles park); patios and walkways 4 inches.
Frequently asked questions
How many bags of concrete in a cubic yard?
About 45 × 80-lb bags or 60 × 60-lb bags. That is why anything over a small repair usually goes ready-mix.
What thickness should a driveway be?
4 inches over a compacted gravel base for cars; 5–6 inches for heavy trucks or RVs. Thickness costs little compared with replacing a cracked slab.
Does this include rebar or mesh?
Quantities here are concrete only. Most slabs also need reinforcement (mesh or rebar) and a gravel base — budget those separately with your supplier.
Planning estimate only — confirm quantities with your supplier before ordering, and keep a little extra material from the same batch for future repairs.