How much concrete do I need?
For slabs, patios, shed bases and footings. Get the volume and the number of bags.
0
How this is calculated
Volume is length times width times thickness. We add a little extra because ground is never perfectly level.
An 80 lb bag of premix yields about 0.6 cu ft, and a 60 lb bag about 0.45 cu ft. For more than about 1 cubic yard, ready-mix delivery is usually cheaper and easier.
How thick should a patio be?
4 inches (10 cm) is standard for patios and walkways. Driveways usually need 5 to 6 inches.
Bags or ready-mix?
Under about 1 cubic yard, bags are practical. Beyond that, mixing by hand becomes very heavy work.