This tool is part of these guided projects. Each project provides step-by-step instructions with checklists and all the tools you need in one place.
Design your deck layout, calculate boards and concrete, plan stairs, and follow a proven build sequence from foundation to finish.
Plan and measure your fence line, calculate materials and concrete, and follow a proven installation process.
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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.
Size concrete footings from column load and soil bearing capacity. Get minimum footing area, dimensions, and bearing pressure for residential foundations.
Full concrete slab material list: volume, gravel base, vapor barrier, and reinforcement. Plan garage floors, patios, and slabs with complete takeoff quantities.
Convert slab thickness from inches to feet by dividing by 12, then multiply length, width, and depth for total volume in cubic feet.
Volume (cu ft) = Length (ft) × Width (ft) × Depth (in) ÷ 12Ready-mix concrete is ordered in cubic yards in the US. One cubic yard equals 27 cubic feet.
Cubic Yards = Cubic Feet ÷ 27Add 10% for spillage, uneven subgrade, and form overfill. Round up to the nearest quarter yard when ordering from a batch plant.
Order (cu yd) = Net Volume (cu yd) × 1.10Updated: July 2026
A homeowner pouring a 24×20 ft garage pad at 4″ thickness needs about 5.9 cu yd net (6.5 cu yd with 10% waste). Order 7 yards to avoid a short load fee.
A 40 ft × 4 ft sidewalk at 4″ deep requires roughly 2.0 cu yd. Use the calculator to confirm before scheduling a Saturday pour with neighbors.
Twelve fence post holes 12″ diameter × 36″ deep total about 0.35 cu yd. Bagged mix (≈45 bags) may be cheaper than a minimum ready-mix load for small pours.
Estimate how much ready-mix concrete or bagged mix you need for slabs, pads, and footings before ordering from the plant. Enter room or pour dimensions in feet and thickness in inches to get cubic yards, cubic feet, and approximate 80 lb bag counts with a standard waste allowance.