Add the separate calculations together for the total square footage of the gardening area. Raised beds give you an immediate advantage over a regular garden, because when you fill your raised bed, you can fill it with a blend of soil that's superior to the native soil in your yard. Calculate your cubic yards: Divide cubic feet by 27 to convert to cubic yards and this is your answer Where (ft 2 ) = square foot, (ft 3 ) = cubic foot, (yd 3 ) = cubic yard Cubic Yards Formulas and â¦ Identify the soil type. Example: there is an area 20 feet by 10 feet and it needs to be 6 inches deep (see Depth Key Code). ... Sod is often sold in pieces of grass and soil, often referred to as pallets or rolls. Soil calculator supporting metric and imperial units - kg, tons, tonnes, cubic meters, cu ft, cubic yards, etc. To use these calculators, simply enter the length and width (or radius), in feet, as well as the depth, in inches, and click the "Calculate" button. Type in inches and feet of your project and calculate the estimated amount of Soil & Dirt in cubic yards, cubic feet and Tons, that your need for your project.