Estimate concrete volume for slabs, pads, and small flatwork projects before ordering ready-mix or bagged concrete.
Driveways, patios, walkways, shed pads, and other rectangular slabs.
A 20 ft × 12 ft slab at 4 in thick is a practical starting example for checking cubic-yard and bag quantities.
Default example result: 3.26 yd³ with 10% allowance.
The calculator uses the displayed formula, applies your waste allowance, and rounds purchase quantities up. Review the assumptions before ordering and confirm product coverage with your supplier.
Formula used: length × width × (thickness ÷ 12) ÷ 27
A 10% allowance is a reasonable starting point for a simple slab, but site conditions and the shape of the pour can justify a different amount.
No. This tool is for preliminary quantity planning and does not replace engineering, local code review, or a supplier confirmation.
This calculator is for preliminary planning and purchasing estimates. It does not replace professional design, local building codes, site conditions, safety checks, or supplier guidance.