Updated April 2026
Concrete Slab Cost Calculator: Find Your Price by Size (2026)
Enter your slab dimensions to get an instant cost estimate with cubic yards required. Covers every standard residential size from 8×8 through 40×80.
Concrete Slab Cost Calculator
How to Read This Table
- Low: 4-inch plain broom finish, no reinforcement, standard 3,000 PSI mix. Suitable for shed pads and light patios.
- Mid: 4-inch, wire mesh reinforcement, broom finish. Standard residential patio or parking pad.
- High: 6-inch, rebar grid, suitable for driveways, garage floors, and heavy loads.
- All estimates include labour. Exclude: excavation, permits, decorative finishes, demolition.
- Regional variation: Northeast/CA add 20–35%; South Central/Southeast subtract 5–10%.
Complete Concrete Slab Cost Table
| Slab Size | Sq Ft | Low (basic) | Mid (standard) | High (reinforced) | Cu Yds (4“) | Cu Yds (6“) | Typical Use |
|---|---|---|---|---|---|---|---|
| 8×8 | 64 | $256 | $480 | $768 | 0.79 | 1.19 | Shed pad, AC unit |
| 8×10 | 80 | $320 | $600 | $960 | 0.99 | 1.48 | Small shed pad |
| 10×10 | 100 | $400 | $750 | $1,200 | 1.23 | 1.85 | Small shed, hot tub |
| 10×12 | 120 | $480 | $900 | $1,440 | 1.48 | 2.22 | Shed / storage |
| 12×12 | 144 | $576 | $1,080 | $1,728 | 1.78 | 2.67 | Patio / storage |
| 10×16 | 160 | $640 | $1,200 | $1,920 | 1.98 | 2.96 | Single car parking |
| 12×16 | 192 | $768 | $1,440 | $2,304 | 2.37 | 3.56 | Small patio |
| 14×14 | 196 | $784 | $1,470 | $2,352 | 2.42 | 3.63 | Patio |
| 10×20 | 200 | $800 | $1,500 | $2,400 | 2.47 | 3.7 | Small patio |
| 12×20 | 240 | $960 | $1,800 | $2,880 | 2.96 | 4.44 | Standard patio |
| 16×16 | 256 | $1,024 | $1,920 | $3,072 | 3.16 | 4.74 | Medium patio |
| 12×24 | 288 | $1,152 | $2,160 | $3,456 | 3.56 | 5.33 | Patio / parking |
| 16×20 | 320 | $1,280 | $2,400 | $3,840 | 3.95 | 5.93 | Large patio |
| 18×18 | 324 | $1,296 | $2,430 | $3,888 | 4 | 6 | Medium patio |
| 16×24 | 384 | $1,536 | $2,880 | $4,608 | 4.74 | 7.11 | Large patio |
| 20×20 | 400 | $1,600 | $3,000 | $4,800 | 4.94 | 7.41 | Large patio / small garage |
| 20×24 | 480 | $1,920 | $3,600 | $5,760 | 5.93 | 8.89 | Patio / sport court |
| 24×24 | 576 | $2,304 | $4,320 | $6,912 | 7.11 | 10.67 | 2-car garage floor |
| 20×30 | 600 | $2,400 | $4,500 | $7,200 | 7.41 | 11.11 | Large patio / RV pad |
| 24×30 | 720 | $2,880 | $5,400 | $8,640 | 8.89 | 13.33 | Large garage |
| 30×30 | 900 | $3,600 | $6,750 | $10,800 | 11.11 | 16.67 | Large garage / workshop |
| 24×40 | 960 | $3,840 | $7,200 | $11,520 | 11.85 | 17.78 | 3-car garage |
| 30×40 | 1,200 | $4,800 | $9,000 | $14,400 | 14.81 | 22.22 | 3-car garage / outbuilding |
| 30×50 | 1,500 | $6,000 | $11,250 | $18,000 | 18.52 | 27.78 | Workshop / outbuilding |
| 40×60 | 2,400 | $9,600 | $18,000 | $28,800 | 29.63 | 44.44 | Small commercial |
| 40×80 | 3,200 | $12,800 | $24,000 | $38,400 | 39.51 | 59.26 | Commercial / large garage |
Worked Example: 20×20 Concrete Slab
A 20×20 ft slab is one of the most common residential sizes — large patio, single-car garage, or sport court pad.
400 sq ft
Area
$3,000
Mid estimate
at $7.50/sqft
2.47 cu yd
Concrete (4-inch)
3.70 cu yd
Concrete (6-inch)
- As a patio: 4-inch, wire mesh, broom finish = $2,400–$4,000 total. Wire mesh recommended for patios with outdoor furniture.
- As a garage floor: 6-inch, rebar grid = $3,200–$5,600 total. Rebar required for vehicle loads.
- As a driveway: 4-inch minimum, wire mesh = $2,800–$5,000 total. Add $500–$1,000 for expansion joints and proper slope.
Standard Sizes by Project Type
| Project | Standard Size | Approx Sq Ft |
|---|---|---|
| Small shed pad | 8×10 | 80 |
| Hot tub base | 10×10 | 100 |
| AC unit pad | 3×3 to 4×4 | 9–16 |
| 1-car garage | 12×20 or 14×20 | 240–280 |
| 2-car garage | 20×20 or 24×24 | 400–576 |
| Small patio | 10×12 to 12×16 | 120–192 |
| Standard patio | 12×20 to 16×20 | 240–320 |
| Large patio | 16×24 to 20×30 | 384–600 |
| RV parking pad | 12×40 to 16×50 | 480–800 |
| 3-car garage | 30×24 to 30×36 | 720–1080 |
Cubic Yards Quick Reference
Formula: (Length × Width × Thickness inches ÷ 12) ÷ 27 = cubic yards. Always add 10% for waste.
| Slab Size | 4-inch slab | 6-inch slab | 4” + 10% waste | 6” + 10% waste |
|---|---|---|---|---|
| 8×8 ft | 0.79 | 1.19 | 0.87 | 1.31 |
| 10×10 ft | 1.23 | 1.85 | 1.35 | 2.04 |
| 10×16 ft | 1.98 | 2.96 | 2.18 | 3.26 |
| 10×20 ft | 2.47 | 3.7 | 2.72 | 4.07 |
| 12×12 ft | 1.78 | 2.67 | 1.96 | 2.94 |
| 12×16 ft | 2.37 | 3.56 | 2.61 | 3.92 |
| 12×20 ft | 2.96 | 4.44 | 3.26 | 4.88 |
| 14×14 ft | 2.42 | 3.63 | 2.66 | 3.99 |
| 16×16 ft | 3.16 | 4.74 | 3.48 | 5.21 |
| 16×24 ft | 4.74 | 7.11 | 5.21 | 7.82 |
| 18×18 ft | 4 | 6 | 4.40 | 6.60 |
| 20×20 ft | 4.94 | 7.41 | 5.43 | 8.15 |
Calculator FAQ
A standard 2-car garage requires a slab of at least 20×20 ft (400 sq ft) for a tight fit, or 24×24 ft (576 sq ft) for comfortable door opening and walking space on each side. Most builders recommend 24×24 as the minimum for a 2-car garage. If you plan to add a workbench area, consider 24×30 or 24×36.