This quantity tool estimates material only. Slab thickness, base, reinforcement, joints, drainage, and strength requirements are design decisions outside the calculation.
01 / Formula
How this is calculated
Cubic yards = length × width × (thickness ÷ 12) × (1 + waste %) ÷ 2702 / Assumptions
What the estimate assumes
- ✓The slab has a rectangular footprint and constant thickness.
- ✓Thickened edges, grade beams, footings, and steps are excluded.
- ✓The waste percentage is editable and applied explicitly.
03 / Worked example
See the math in context
A 20 × 24 ft slab at 4 inches thick is 160 cubic feet, or 5.93 cubic yards before waste.
04 / Guidance
Thickness is not a recommendation
The calculator accepts the thickness you specify. Select it from project plans, applicable requirements, manufacturer guidance, or a qualified professional—not from the quantity result.
Questions
Frequently asked
Should I order exactly the calculated amount?+
Usually no. Excavation variation, form dimensions, spillage, and uneven subgrade can increase actual volume. Use the editable waste allowance and discuss minimum loads and order increments with the supplier.
How many cubic feet are in a cubic yard?+
There are exactly 27 cubic feet in one cubic yard. Divide cubic feet by 27 to convert to cubic yards.
Does this replace a structural design?+
No. These tools estimate material quantity only. A qualified professional and applicable plans, codes, site conditions, reinforcement requirements, and manufacturer instructions govern the project.
Sources