Concrete Slab Calculator

Calculate concrete volume for flat slabs β€” patios, garage floors, driveways, and walkways. Get cubic yards, bags, and ready-mix cost.

⬜ Concrete Slab Calculator

Results

Volume80.00 cu ft
Volume2.96 cu yd
Order (+10% waste)3.26 cu yd
80 lb Bags134 bags
Ready-Mix Cost$423.70

πŸ’‘ How to Calculate Concrete Slab Volume

Slab volume = length Γ— width Γ— thickness. Standard residential slab thicknesses: sidewalks and patios = 4 inches, garage floors and driveways = 4–6 inches, heavy-duty industrial = 6–8 inches. Order 10% extra for waste, uneven subgrade, and form variations.

Ready-mix concrete is sold by the cubic yard and costs $120–$160 per yard in most markets. For small jobs under 1 cubic yard, bagged concrete may be more practical. One cubic yard fills a 10Γ—10 ft slab at 3.24 inches thick.

A 20Γ—12 ft patio at 4 inches thick: 20 Γ— 12 Γ— 0.33 = 80 cu ft = 2.96 cu yd. Order 3.26 cu yd (+10%). At $130/yd, ready-mix cost β‰ˆ $424.

Concrete Slab Calculator FAQ

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