Concrete Slab Calculator
Published On: 02/03/2026
Concrete Slab Calculator
Estimate the amount of concrete needed for a rectangular slab, plus optional waste factor and quick conversions to cubic yards and cubic meters.
Inputs explained:
• Length and Width: slab dimensions.
• Thickness: slab depth (often 4 in for patios/walkways, thicker for driveways/structures).
• Waste factor: extra concrete for spillage, uneven subgrade, and over-excavation (commonly 5–10%).
The calculator outputs volume in ft³, yd³, and m³.
• Length and Width: slab dimensions.
• Thickness: slab depth (often 4 in for patios/walkways, thicker for driveways/structures).
• Waste factor: extra concrete for spillage, uneven subgrade, and over-excavation (commonly 5–10%).
The calculator outputs volume in ft³, yd³, and m³.
In Metric mode, set this to meters.
Tip: Ready-mix suppliers typically sell concrete by the cubic yard (US) or cubic meter (many other countries).
Concrete Slab Calculator — Description
The Concrete Slab Calculator estimates how much concrete you need for a rectangular slab based on length, width, and thickness. It also includes an optional waste factor to account for uneven ground, spillage, and over-excavation. Results are shown in cubic yards, cubic feet, and cubic meters so you can order the correct amount of ready-mix concrete.
Use this tool for patios, walkways, driveways, shed pads, and other flat concrete pours.