### How to Estimate Stone Walls | Hunker

Use the standard formula of 15 cubic feet of gravel = 1 ton of gravel. Divide the total cubic foot volume of gravel by 15 to determine the number of tons of gravel to purchase. For example, 80 cubic feet of gravel divided by 15 equals 5.333 tons. You will need to order 6 tons of gravel for this wall.