How Much Does a Concrete Slab Cost? (2026)
Updated
A concrete slab costs about $4 to $8 per square foot for a standard 4-inch pour, or roughly $6 to $12 for thicker, reinforced, or finished slabs. A 20×20 ft slab (400 sq ft) typically runs $1,600 to $3,200 installed, including the concrete, base, and labor.
A concrete slab is the foundation for sheds, garages, patios, driveways, and home additions. Pricing it right means understanding not just the concrete itself, but the base prep, reinforcement, thickness, and labor that go into a lasting slab.
This guide breaks down concrete slab costs in 2026 — per square foot, by common size, and by thickness — so you can budget before you order and spot a fair quote.
Key takeaways
- Standard 4-inch slabs cost about $4–$8 per square foot installed.
- Thicker, reinforced, or finished slabs run $6–$12 per square foot.
- A 20×20 ft slab (400 ft²) typically costs $1,600–$3,200.
- Concrete material alone is about $120–$165 per cubic yard (ready-mix).
- Base prep, rebar, and labor make up most of the price.
Skip the math
Get instant numbers with the Concrete Calculator.
Concrete slab cost by size
Slabs are priced per square foot. The table shows typical installed costs for common sizes at a standard 4-inch thickness with a basic finish.
| Slab size | Area | Installed cost |
|---|---|---|
| 10 × 10 ft | 100 ft² | $400 – $800 |
| 12 × 12 ft | 144 ft² | $575 – $1,150 |
| 20 × 20 ft | 400 ft² | $1,600 – $3,200 |
| 24 × 24 ft (garage) | 576 ft² | $2,300 – $4,600 |
Cost by thickness
Thickness drives both the concrete volume and the slab's load capacity. Going from 4 to 6 inches uses 50% more concrete.
| Thickness | Typical use | Cost per ft² |
|---|---|---|
| 4 inches | Patios, sheds, walkways | $4 – $6 |
| 5 inches | Driveways, light vehicles | $5 – $8 |
| 6 inches | Garages, heavy loads | $6 – $10 |
What's included in the price
- Excavation and grading of the site
- A compacted gravel base for drainage and support
- Forming the slab edges
- Rebar or wire mesh reinforcement
- The ready-mix concrete itself
- Pouring, screeding, and finishing labor
How to estimate concrete for a slab
For materials, calculate the volume: length × width × thickness (in feet), divided by 27 for cubic yards. A 20×20 ft slab at 4 inches needs about 4.9 cubic yards.
Our concrete calculator returns the exact cubic yards, bag counts, and a ready-mix cost range when you enter your slab dimensions.
Ways to save on a concrete slab
- Keep the shape simple — square and rectangular slabs are cheapest.
- Order ready-mix for anything over a cubic yard instead of bags.
- Schedule in the off-season for better labor rates.
- Combine multiple slabs into one pour and delivery.
- Do your own site prep if you're able.