Tools you might need next
Free concrete calculator for slabs, footings, and pours. Enter length, width, depth to get cubic yards, cubic feet, and bag counts with waste factor.
Calculate rebar quantity and spacing for concrete slabs. Enter slab size, bar spacing, and stock length to get bar count, linear feet, and sticks to buy.
Calculate gravel cubic yards for driveways, paths, and drainage. Enter area and depth to get tons, cubic yards, and dump truck loads for crushed stone projects.
Calculate slab volume in cubic yards with 10% waste for overpour and subgrade variation.
Concrete (cu yd) = (L × W × Thickness/12 ÷ 27) × 1.10Compactible gravel (typically 4″) goes below the slab for drainage and uniform support. Order crushed stone or road base by the cubic yard.
Gravel (cu yd) = (L × W × Gravel Depth/12 ÷ 27) × 1.10Wire mesh (6×6 W1.4) covers ~150 sq ft per roll. #4 rebar at 18″ OC uses floor(span/spacing)+1 bars each direction times run length.
Mesh rolls = ceil(Slab Area ÷ 150); Rebar LF per spacing gridUpdated: July 2026
384 sq ft × 4″ slab: ~4.7 cu yd concrete, ~1.6 cu yd gravel, 3 rolls of wire mesh, and 422 sq ft of 6 mil vapor barrier.
144 sq ft patio with #4 @ 18″ OC needs 9 bars each way (~108 LF) plus 0.6 cu yd concrete. Rebar suits heavier furniture loads or expansive soil.
Small utility pad with no reinforcement still needs gravel base and vapor barrier. Calculator shows 0.25 cu yd concrete — bag mix may beat ready-mix minimum load.
Get a complete material takeoff for a concrete slab on grade — not just concrete volume but gravel base, vapor barrier, and reinforcement options. Ideal for garage floors, patios, and shed pads where you need one list before calling suppliers.