Concrete Slab Calculator
Calculate concrete volume for flat slabs โ patios, garage floors, driveways, and walkways. Get cubic yards, bags, and ready-mix cost.
โฌ 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
๐ก How to Calculate Concrete Slab Volume
Slab volume = length ร width ร thickness. Standard residential slab thicknesses: sidewalks and patios = 4 inches, garage floors and driveways = 4โ6 inches, heavy-duty industrial = 6โ8 inches. Order 10% extra for waste, uneven subgrade, and form variations.
Ready-mix concrete is sold by the cubic yard and costs $120โ$160 per yard in most markets. For small jobs under 1 cubic yard, bagged concrete may be more practical. One cubic yard fills a 10ร10 ft slab at 3.24 inches thick.
A 20ร12 ft patio at 4 inches thick: 20 ร 12 ร 0.33 = 80 cu ft = 2.96 cu yd. Order 3.26 cu yd (+10%). At $130/yd, ready-mix cost โ $424.