Concrete Bags, Gravel Tons & Mulch Cubic Yard Calculator

Cubic Yards of Concrete, Gravel & Mulch: Order Exactly Enough

Bulk materials are sold by the cubic yard, but every project you measure is in feet and inches — and that unit gap is where expensive mistakes happen. The conversion is simple once you see it: multiply length × width × depth in feet, then divide by 27, because a cubic yard is 3×3×3 feet. A 10-by-12-foot patio at 4 inches deep (a third of a foot) needs 10 × 12 × 0.333 ÷ 27 ≈ 1.48 cubic yards. Order 1.5 and you are covered; order "about a yard" from memory and the truck leaves with your slab half-poured.

Each material has its own depth logic, and guessing the depth is the real skill. Concrete slabs for patios and walkways typically go 4 inches thick (6 for driveways bearing cars), gravel driveways want 3 to 4 inches compacted, and mulch beds are happiest at 2 to 3 inches — deeper smothers plants, shallower lets weeds through. Bagged concrete is the backup plan for small jobs: an 80-pound bag yields about 0.6 cubic feet, so that 1.48-yard patio would need an absurd 67 bags, which is exactly why anything over half a yard deserves a ready-mix delivery.

The pro move is the waste factor, and skipping it is the classic DIY error. Pros order 5 to 10 percent extra for concrete because forms leak, subgrades are never perfectly level, and running short mid-pour creates a cold joint that permanently weakens the slab. For gravel and mulch, 10 percent covers settling and the thin spots you always notice the next morning. Enter your dimensions, pick the material, set your depth, and the calculator returns cubic yards, cubic feet, bag counts, and the padded order quantity — the number you actually call the yard with.