# How do i determine how much concrete is needed for a patio slab?

### 4 Comments on “How do i determine how much concrete is needed for a patio slab?”

1. Multiply your slab form width by the length and then multiply that total by 0.33 for a four inch slab Divide that total by twenty seven to get your amount in cubic yards of concrete.

2. Patio slabs are usually four inches thick. So every three sq. ft. of slab is 1 cubic feet of concrete. There is twenty seven cubic feet of concrete in one cubic yard of concrete.
So one cubic yard of concrete will do eighty one sq. ft. of patio. You need also to allow for waste so order to the highest cubic yard. Like if you calculate 1.75 cubic yards order two cubic yards.

3. You measure the surface area of your chosen site, then multiply that figure by the thickness of the concrete. For a patio the concrete should be 4 inches thick and the sub-base should also be 4 inches thick. Hope this helps, it was my Fathers calculations.

4. Lengh x Width x Depth all in the same units.