How much does a 10x10 concrete slab cost?

In the United States, pouring a 10x10 foot concrete slab (100 sq ft at 4 inches thick) typically costs between $150 and $250 in DIY materials (bags or delivered ready-mix). Professionally installed slabs average between $6.00 and $10.00 per square foot ($600 to $1,000 total) including excavation, subbase, rebar, and finishing.

How many bags of concrete do I need for a 12x12 slab 4 inches thick?

A 12x12 slab at 4 inches thick is 48 cubic feet (1.78 cubic yards). With a 10% waste margin, you need approximately 88 bags of 80 lb concrete or 117 bags of 60 lb concrete.

Concrete Slab Calculator — Cubic Yards, Bags & Cost

Concrete Slab Requirements for Popular Sizes (4" Slab)

Slab Size	Square Footage	Cubic Yards (w/ 10%)	80 lb Premix Bags	Est. DIY Material Cost
10 × 10 ft Slab	100 sq ft	1.35 yd³	61 bags	$360 – $420
12 × 12 ft Slab	144 sq ft	1.95 yd³	88 bags	$520 – $610
12 × 16 ft Slab	192 sq ft	2.60 yd³	117 bags	$690 – $800
16 × 24 ft Garage	384 sq ft	5.20 yd³	Ready-Mix Truck	$850 – $1,100 (Bulk)

How to Calculate a Concrete Slab

A concrete slab calculation requires measuring the surface area and converting the thickness from inches into feet.

Mathematical Slab Formula:

1. Area (sq ft) = Length (ft) × Width (ft)

2. Thickness in Feet = Thickness in Inches ÷ 12

3. Cubic Feet = Area × Thickness in Feet

4. Cubic Yards = (Cubic Feet ÷ 27) × (1 + Waste Percentage / 100)

Frequently Asked Questions

Do I need gravel under a concrete slab?

Yes. Pouring concrete directly onto soil causes premature cracking from freeze-thaw cycles and poor drainage. A compacted 4-inch base of crushed gravel (#57 stone or Crusher Run) provides a solid, level foundation.

How long before I can walk on a new concrete slab?

You can typically walk on new concrete within 24 to 48 hours. Avoid placing heavy machinery or vehicles on the slab for at least 7 to 10 days, as full structural cure requires 28 days.

Related Calculators

Concrete Calculator →Footings, columns, and walls.Driveway Calculator →Driveway concrete & subbase tons.Gravel Calculator →Crushed stone subbase quantities.