To find how many cubic yards you need for a project, multiply the length in feet by the width in feet, then multiply by the depth in feet (to convert inches to feet, divide the inches by 12). This calculation gives you total cubic feet. Divide that number by 27, because there are exactly 27 cubic feet in a single cubic yard. Formula: (Length × Width × (Depth ÷ 12)) ÷ 27 = Cubic Yards.
Ordering material strictly by volume can lead to mistakes because different materials have vastly unique densities. For example, 1 cubic yard of fine packing materials like Limestone Screenings weighs roughly 1.50 tons because the particles pack tightly with almost zero air gaps. Conversely, 1 cubic yard of Large River Rock (1"-3") fills the same spatial volume but only weighs roughly 1.28 tons due to the natural air pockets between loose, larger stones.
Determining your project depth depends heavily on use-case stress factors. For residential gravel driveways supporting vehicles, a total aggregate depth of 4 to 6 inches is standard to establish a stable structural base. For pedestrian walkways, garden paths, decorative river stone borders, or landscape wood mulch placement, a shallower depth of 2 to 3 inches is ideal to prevent sinking while conserving material costs.
Recycled asphalt millings have become an incredibly popular choice for budget-friendly driveway restorations. When loose and uncompacted, asphalt millings carry an approximate math density multiplier of 1.25 tons per cubic yard. When spread smoothly at a 4-inch depth and rolled tightly with a heavy vibratory compactor, the sticky bitumen binds the stones together, hardening into a semi-permanent surface that seals out dust and resists heavy rainfall erosion.