Guide
How to Calculate Concrete Cubic Yards
Concrete volume starts with slab dimensions in feet and depth in inches. Convert to cubic yards before ordering ready-mix or bags.
Construction CalculatorsIncludes Concrete Calculator
Volume formula
Cubic feet = length (ft) × width (ft) × depth (in) ÷ 12. Cubic yards = cubic feet ÷ 27.
Add 5–10% waste for spills and uneven subgrade on larger pours.
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Frequently asked questions
How many bags per yard?
Roughly 45 eighty-pound bags per cubic yard for back-of-envelope estimates—verify with your mix spec.
Last reviewed: 2026-06-02