How Much Will a Yard of Concrete Cover?

Square Footage Coverage of One Cubic Yard of Concrete by Slab Thickness

Concrete in the construction industry is universally ordered and sold by the cubic yard, which represents a three-dimensional volume measuring three feet wide by three feet long by three feet deep (3 x 3 x 3 = 27 cubic feet). To calculate how many cubic yards your project requires, contractors multiply length in feet by width in feet by depth in feet, and then divide that total cubic footage by 27. Because slab depth is typically specified in inches, converting inches into a fraction of a foot is the foundational mathematical step.

Experienced masons and concrete contractors always incorporate an additional ten percent safety buffer into their ready-mix truck orders. A job site is never a perfectly engineered laboratory mold; variations in ground excavation depth, settling of compacted gravel subbase, bowing of wooden 2x4 form boards under hydrostatic wet concrete pressure, and residual concrete clinging inside the delivery truck drum can quickly exhaust your calculated volume. Running short during a continuous pour creates unsightly cold joints and expensive emergency delivery charges.

Slab thickness dictates the surface area coverage achieved per cubic yard of concrete. Review square footage coverage figures and typical residential applications in the table below.

Subbase Compaction, Formwork Deflection, and the Critical 10 Percent Waste Factor

Understanding the mathematical formula for concrete volume prevents costly ordering errors. The standard formula is: Length (feet) multiplied by Width (feet) multiplied by Depth (feet), divided by 27. For example, to pour a 12-foot by 15-foot backyard patio at a standard depth of 4 inches, convert 4 inches to feet by dividing 4 by 12, which equals 0.333 feet. Multiplying 12 by 15 by 0.333 produces 59.94 cubic feet. Dividing 59.94 by 27 yields 2.22 cubic yards. Adding a ten percent contingency of 0.22 brings the final order to 2.5 cubic yards.

Subgrade preparation directly dictates whether your calculated yardage will be sufficient during the pour. If an excavator digs unevenly or leaves low spots in the dirt base, wet concrete will fill those depressions. A low spot just one inch deeper than planned across a twenty-by-twenty-foot slab area consumes an extra 1.23 cubic yards of concrete—nearly an entire extra ton of material. Ensuring your crushed gravel base is leveled with laser levels and compacted firmly with a vibrating plate compactor prevents massive volume shortfalls.

Compare ready-mix truck yardage requirements against standard 60-pound and 80-pound pre-mixed concrete bags for typical residential homeowner installations.

Pouring Slabs, Sidewalks, Driveways, and Footings: Practical Volume Estimations

Homeowners often debate whether to mix concrete bags by hand or order a ready-mix concrete delivery truck. A standard 80-pound bag of pre-mixed concrete yields approximately 0.60 cubic feet of wet concrete, meaning it takes 45 bags of 80-pound concrete to equal just one single cubic yard (27 cubic feet). For a 60-pound bag yielding 0.45 cubic feet, it requires 60 bags per cubic yard. While mixing 15 or 20 bags for a mailbox post or small step repair is practical, hand-mixing 100 or 200 bags for a patio is physically exhausting, slow, and leads to inconsistent batch strengths.

Ready-mix concrete delivery services are the gold standard for projects requiring more than one cubic yard. Ready-mix trucks typically carry eight to ten cubic yards of computer-batched concrete, ensuring consistent water-cement ratios, compressive strength (typically 3,000 to 4,500 PSI), and proper air entrainment for freeze-thaw durability. However, ready-mix dispatchers assess short-load fees ranging from $100 to $250 if ordering less than four or five cubic yards, which should be factored into your project budget.

Managing site accessibility and delivery unloading time avoids steep carrier penalties. Ready-mix dispatch contracts typically include five to seven minutes of unloading time per cubic yard. If the truck must sit idle because your wheelbarrow crew cannot transport concrete to the backyard fast enough, companies charge demurrage fees of $2 to $4 per minute. For locations with narrow gates, steep slopes, or long distances from the street curb, renting a concrete line pump or motorized concrete buggy pays for itself by allowing rapid, seamless placement.