Concrete Calculator
Concrete is ordered in cubic yards in the US. Volume in cubic feet is length × width × thickness (all in feet), then divide by 27. Add a waste factor because forms are imperfect.
Cubic feet66.67
Cubic yards (with waste)2.72
Cubic meters1.888
Estimate only. Confirm with your supplier.
Formula
yd³ = (L × W × (inches÷12)) ÷ 27, then × (1 + waste%).
How to use this calculator
- Enter slab length and width in feet.
- Enter thickness in inches.
- Add waste (10% is common).
Examples
20×10 ft, 4 in, 10% waste
Base 2.47 yd³, with waste about 2.71 yd³.
FAQ
Bags or ready-mix?+
This is volume. Bag yield is on the bag — typically 0.45–0.6 ft³ per 80 lb bag.
Related tools
CalculatorSquare Footage CalculatorCalculate room or lot area from length and width, with optional extra rooms.CalculatorPaint CalculatorEstimate gallons of paint from wall area, coats, and coverage per gallon.CalculatorFlooring CalculatorEstimate flooring material from room area plus a waste factor.CalculatorTile CalculatorEstimate how many tiles you need from area, tile size, and waste.CalculatorRoofing Squares CalculatorConvert roof area into roofing squares (100 sq ft) with pitch factor.CalculatorGravel CalculatorEstimate tons of gravel from area, depth, and density.CalculatorMulch CalculatorEstimate cubic yards of mulch from bed area and depth.CalculatorDrywall CalculatorEstimate 4×8 drywall sheets from wall and ceiling area.