It requires two 80-pound bags of standard concrete mix for a 4- to 6-inch-thick concrete slab that is 2.0801 square feet, which is equal to 3 cubic feet. So, two 90-pound bags of concrete should get the job done.
When purchasing concrete mix, it is important to consider the depth of the pour area in addition to the area. The type and brand of concrete that is purchased may also affect the amount needed. Make sure to read all packaging to help determine how much is required. It is always a good idea to have extra concrete mix on hand in case a batch is mixed too thinly.