Concrete Slab Cost Calculator

A typical concrete slab costs between $4 to $8 per square foot for a 4-inch thick slab, or about $125 to $165 per cubic yard for ready-mix concrete. A standard 10×10 ft slab (4 inches thick) costs approximately $170 to $225 for materials only. Costs vary by region, concrete mix type, and delivery fees.

For most residential applications, a 4-inch (10 cm) thick slab is standard. Driveways and garage floors typically need 5 to 6 inches. Heavy-duty commercial floors may require 6 to 8 inches. Always consult local building codes for load-bearing slabs.

A waste factor of 5% to 10% accounts for spillage, uneven ground, over-excavation, and form irregularities during a pour. We recommend 10% for most projects. It's better to have slightly more concrete than to run short during a pour.

Small slabs (up to about 4×4 ft) are manageable for DIY using bagged concrete mix. For larger slabs, ordering ready-mix concrete is more practical and cost-effective. You'll need proper formwork, a level base of compacted gravel, and reinforcement (rebar or wire mesh). Always check local permits before starting.

The number of bags depends on your slab dimensions. An 80 lb bag covers approximately 0.6 cubic feet. For a 10×10 ft slab at 4 inches thick, you'd need about 56 bags (80 lb) without waste, or 62 bags with 10% waste. For slabs larger than 1 cubic yard, ordering ready-mix is usually more economical.