Confirm ready-mix delivery
Ask the batch plant about minimum orders, delivery increments, mix specification, access, and short-load charges.
Continue planning
How the calculation works
We use 150 lb/ft³ normal-weight planning value.
Formula: length × width × slab thickness ÷ 27, plus waste
Worked example
A 12 × 10 ft slab at 4 in deep, plus 10% waste, requires about 1.7 cubic yards.
Measure the finished slab
Use inside form dimensions and the specified uniform thickness; calculate thickened edges or footings separately.
Frequently asked questions
Does this include footings?
No. Add footing and thickened-edge volumes as separate shapes.
Why add a waste allowance?
Subgrade variation, form dimensions, and handling can make delivered volume differ from ideal geometry.
Sources and assumptions
Exact cubic-foot conversion with a 150 lb/ft³ normal-weight concrete planning value.
Last reviewed: August 14, 2026. Read the methodology and sources.