About 1/2 cubic yard will be enough.
1.25 cubic yards for a 4-inch slab. 2 cubic yards (1.85) for a 6-inch slab.
800lbs
For a 4-inch thick slab you will need at least 1.2 cubic yards.
10-ft x 30-ft x 4-in = 100 cubic ft.That slab weighs 3.7 times as much as 1 "yard" of concrete. (rounded)
3.16 Cubic Yards
128
A 10-foot round slab at 4 inches requires 1 cubic yard.
At least 3 cubic yards for a 4-inch slab. You'll need 4.75 cubic yards for a 6-inch slab.
For a 4-inch depth you will need at least 7 cubic yards.
22 cubic yards
A 22x22 foot slab at a 4-inch thickness/depth requires a minimum of 6 cubic yards.
how many yards of concrete will i need to do a 20 x20 x4 slab