Concrete yardage is the volume of concrete needed to fill slabs, footings, and structural elements on a residential project. Concrete is ordered and billed by the cubic yard, and accurate takeoff prevents costly short orders and overages.
The formula
Convert all dimensions to feet, multiply length by width by thickness, then divide by 27 (the number of cubic feet in a cubic yard):
Cubic Yards = (Length × Width × Thickness in feet) ÷ 27For projects with slabs, footings, and piers, calculate each separately, then add them together. Always add a 10% waste factor to account for spillage, equipment settle, and over-pour on final elevation.
Worked example: 926 Stratford
The seed project is a 1,784 sq ft house with a concrete slab-on-grade foundation and standard strip footings. Here is the breakdown:
Slab calculation
- Slab area: 1,784 sq ft (same as house footprint)
- Slab thickness: 4 inches = 0.333 feet
- Cubic yards: (1,784 × 0.333) ÷ 27 = 22.0 cubic yards
Footing calculation
- Perimeter of 1,784 sq ft footprint (approximately 44 × 40): roughly 168 linear feet
- Add for interior bearing walls: add 32 linear feet, total 200 linear feet
- Footing width: 16 inches = 1.33 feet
- Footing depth: 8 inches below grade = 0.667 feet
- Footing volume: (200 lf × 1.33 × 0.667) ÷ 27 = 6.6 cubic yards
Total and waste
- Slab + footings: 22.0 + 6.6 = 28.6 cubic yards
- 10% waste factor: 28.6 × 1.10 = 31.5 cubic yards
- Order: 32 cubic yards (round to nearest whole truck capacity)
A standard ready-mix truck carries 9 to 10 cubic yards. This project would need four trucks. Anything under 3 cubic yards triggers a short-load fee (typically $100 to $200 per truck), so over-ordering slightly is preferable to a return trip.
Inputs and what they mean
Length, width, thickness (feet)
Always measure and convert to feet before calculating. A 4-inch slab is 0.333 feet (4 ÷ 12). An 8-inch footing is 0.667 feet. Most slabs on grade are 4 inches; basements might be 6 inches (thicker, stiffer). Folded slabs (thickened edges) require a separate calculation for the thickened band.
Cubic yards as the unit
Concrete is ordered by cubic yards. One cubic yard is 27 cubic feet. A truck carrying 9 yards holds 243 cubic feet. Rounding up to a whole truck is normal practice. Partial trucks incur charges.
Continuous footings: the standard condition
Most residential foundations use continuous footings (a concrete strip running under the perimeter and under interior bearing walls). A typical footing is 16 inches wide and 8 to 12 inches deep. Colder climates require deeper footings to avoid frost heave, so a zone in Minnesota might be 4 feet deep, while Tennessee might be 2 feet.
Calculate footing volume as a long rectangle: linear footage × width × depth ÷ 27. Interior bearing walls need footings too. A center support beam in a 44 × 40 house runs roughly 40 feet and needs its own footing.
Piers and spot footings
Posts on piers are cylindrical holes filled with concrete. The volume of a cylinder is π r² h (pi times radius squared times height). A 12-inch-diameter pier (6-inch radius = 0.5 feet) that is 4 feet deep has volume of 3.14 × 0.5² × 4 = 3.14 cubic feet = 0.116 cubic yards. A house might have 4 to 6 piers, totaling roughly 0.5 to 0.7 cubic yards.
Concrete strength and slump
Concrete is specified by compressive strength (PSI) and slump (workability). Standard residential concrete is 3,000 PSI with a 4-inch slump. Cold climates sometimes specify 3,500 PSI to resist freeze-thaw cycles. Air entrainment (tiny bubbles) protects against frost damage and adds $8 to $15 per yard.
Slump affects pumpability and finish. A 6-inch slump is wetter and easier to pump up a chute or through a boom but can bleed (water separating from solids). A 4-inch slump is stiffer and requires more work to finish. Finishers will add water on site if slump is too stiff, which weakens the concrete. Specify slump clearly with your supplier.
Edge cases and pitfalls
Frost depth varies by region
Northern climates (Minnesota, Wisconsin, New York) require footings 3 to 4 feet deep to get below frost line. Southern climates (Tennessee, Georgia) might only be 2 feet. A Tennessee footing at 2 feet deep saves concrete compared to a Minnesota foundation at 4 feet. Always verify the local building code minimum frost depth before ordering.
Sloping grades and step footings
On sloped sites, footings step down in increments (usually 12 or 16 inches, one story height) to follow grade. Calculate the average footing depth or split the footing into segments at each step. A house with a 6-foot grade drop needs at least two or three stepped footing sections.
Thickened slab edges
Some designs thicken the slab perimeter band to 6 or 8 inches instead of using a separate footing. Calculate the main 4-inch slab, then add the extra 2 or 4 inches on the perimeter band separately. A 200-foot perimeter, 4-inch-thick band, and 2-inch thickening adds roughly 1.5 cubic yards.
Rebar, wire mesh, and vapor barriers
Rebar and wire mesh do not increase concrete volume (they are negligible), but they increase cost and labor. Budget separately. Vapor barriers (6-mil poly sheeting under slabs) cost $0.10 to $0.15 per sq ft.
Related material costs (2026 pricing notes)
Ready-mix concrete
Standard 3,000 PSI concrete (residential grade) costs $180 to $250 per cubic yard, depending on market and distance from the plant. A 32-yard pour costs $5,760 to $8,000 just in concrete. Premium mix designs (higher PSI, air entrainment, fiber reinforcement) add $20 to $40 per yard.
Short-load charges
Orders under 3 cubic yards incur a short-load fee of $100 to $200 per truck. If you need 1 extra yard, it is cheaper to buy a full truck (9 yards) than to add a short-load charge. Plan ahead to consolidate orders.
Pump truck rental
If concrete cannot be delivered directly to the pour location (tight site access, elevated placement), a pump truck is required. Pump trucks cost $500 to $800 for a single job, plus the cost to move and set up the boom. Factor this into your estimate if the site layout suggests pumping will be needed.
Finishing and placement labor
Concrete placement and finishing costs roughly $50 to $150 per cubic yard in labor and equipment, depending on the complexity of the finish. A simple broom finish on a slab is cheaper than a smooth troweled finish. Specialty finishes (stamped, stained) are significantly more.
Rebar and wire mesh
Rebar costs $0.40 to $0.60 per pound. A residential slab typically uses 0.15 to 0.20 pounds of rebar or wire mesh per square foot, or $50 to $200 per 1,000 sq ft slab. Wire mesh is typically cheaper but less effective at controlling cracks than rebar.
How BuilderGrid uses this calculator
The concrete calculator sits in the materials module alongside roofing, framing, and finishes. Input slab area, footing dimensions, pit and pedestal counts, and the tool calculates total cubic yards with the 10% waste factor baked in. The system tracks supplier pricing and delivery fees so you can see the all-in cost per yard for your market. When the slab contractor invoices, the variance is logged and feeds into cost-to-complete forecasting for the project.