**A 2-cubic-foot bag of mulch covers 6 square feet at a depth of 4 inches, 8 square feet at a depth of 3 inches and 12 square feet at a depth of 2 inches.** At a depth of 2 inches, a 3-cubic-foot bag covers 18 square feet.

That same bag covers 12 square feet at a depth of 3 inches and 9 square feet at a depth of 4 inches.

To calculate the necessary number of bags to adequately cover a certain area with mulch, the area of the space must be measured, multiplying length times width. Then, the desired thickness of the layer must be determined.