### Concrete Calculator

Apr 23, for concrete, the formula for volume is as follows: length x width x thickness. to determine how many bags of concrete you will need, divide the total cubic yards needed by the yield. use the following yields per each bag size: 40 pound bag yields .011 cubic yards. 60 pound bag yields .017 cubic.Apr 29, low: $300. (10 x 20-ft. driveway, 3-inches thick) high: $600. (10 x 20-ft. driveway, 4-inches thick, two colors) get local cost. invalid zip code find yours. cost to have concrete delivered varies greatly by region (and even by zip code). get free estimates from concrete contractors in your city. get local.