Concrete Slab Cost Calculator
Your estimate
- Cost per ft² / m²
- $7.24
- Concrete
- $896
- Labor & finishing
- $1,600
- Reinforcement & extras
- $400
- Concrete (with waste)
- 5.43 yd³146.7 ft³ · 4.15 m³
- Area
- 400 ft²44.44 yd² · 37.16 m²
Material, labor and reinforcement add up to the total — change any price to match your quotes.
Updated 2026-10-20 · Based on: bag yields printed by concrete-mix makers (0.30–0.60 ft³ per bag) and a 1.54 dry-volume factor.
How to use the Concrete Slab Cost Calculator
- Enter the slab size and thickness.
- Type the ready-mix price per cubic yard from your local supplier.
- Add labor and finishing per square foot (forming, placing, finishing) and reinforcement per square foot.
- Compare the cost per square foot with contractor quotes.
Formula
Material = cubic yards (with waste) × price per yard. Labor and extras = slab area × price per ft².
Total = material + labor + extras; cost per ft² = total ÷ area.
Worked example
With the values preset in the calculator above:
- Length
- 20 ft
- Width
- 20 ft
- Thickness
- 4 in
- Extra for waste
- 10 %
- Total cost
- $2,896
- Cost per ft² / m²
- $7.24
- Concrete
- $896
- Labor & finishing
- $1,600
- Reinforcement & extras
- $400
How much does a concrete slab cost?
With the default prices ($165/yd³ concrete, $4/ft² labor, $1/ft² reinforcement) a 20 × 20 ft slab 4 in thick comes to $2,896, or $7.24 per square foot. Most US quotes in 2026 fall between $6 and $12 per ft² depending on thickness, access and finish (broom, stamped, colored).
Slab cost by size (default prices)
| Length (ft) | Width (ft) | Thickness (in) | Area | Total cost |
|---|---|---|---|---|
| 10 | 10 | 4 | 100 ft² | $704 |
| 12 | 12 | 4 | 144 ft² | $1,013 |
| 20 | 20 | 4 | 400 ft² | $2,815 |
| 24 | 24 | 4 | 576 ft² | $4,053 |
| 24 | 24 | 6 | 576 ft² | $4,640 |
| 30 | 30 | 6 | 900 ft² | $7,250 |
Related guides
Frequently asked questions
How much does a 24×24 concrete slab cost?
At 4 in thick and the default prices a 24 × 24 ft slab costs about $4,171. Thicker slabs, stamping or long pumping distances raise the price.
What adds the most to slab cost?
Labor and finishing usually cost more than the concrete itself. Site prep (excavation, gravel base), pumping and decorative finishes are the other big items.
How can I lower the cost of a slab?
Keep the thickness to what the use needs, order full truck loads to avoid short-load fees, and do the gravel base and forms yourself.
More calculators
Estimates only — check quantities with your supplier and local building code before you order.