How many 80 lb bag cement to make 10x12 slab 3in thick?

To calculate the number of 80 lb bags of cement needed for a 10x12 foot slab that is 3 inches thick, first determine the volume of the slab in cubic feet: 10 ft x 12 ft x (3/12) ft = 30 cubic feet. One 80 lb bag of cement typically yields about 0.6 cubic feet of concrete. Therefore, you would need approximately 30 / 0.6 = 50 bags of 80 lb cement to complete the slab.