STEP #1: To calculate the size, measure the length and the width of your project area. Multiply those two numbers to come up with the square footage of your coverage area. 

STEP #2: Decide how deep you want your coverage. For most purposes, 2 inches of material will be adequate. If you’re using materials that are themselves larger than 2 inches, then the depth will probably be the size of the rocks. 

STEP #3:  The amount of landscaping rock you’ll need depends partly on what size of rock or gravel you want to use. This chart gives you an estimates of how much area 1 ton of rock will cover per ton.