12x12 Concrete Slab Cost & Calculator
Instant answer: A 12×12 ft slab at 4 inches contains 1.78 cubic yards. Installed: $864–$1,440. DIY material: $310–$480.
Pre-filled to 12×12 ft at 4 inches. Change inputs to recalculate.
Average ready-mix concrete costs $120-$200 per cubic yard.
Calculation Results
Volume
1.78 cubic yards
1.36 m³
Estimated Cost
$266.67
at $150/yd³
Bags Needed
162
40 lb bags
105
60 lb bags
81
80 lb bags
Truck Loads
0.18
10 yd³ per truck
Recommended Mix
Bags (DIY)
Standard 3000 PSI mix
12x12 Slab at Different Thicknesses
| Thickness | Cubic Yards | Material Cost | Installed |
|---|---|---|---|
| 3" | 1.33 | $200-$300 | $648-$1,080 |
| 4" | 1.78 | $270-$430 | $864-$1,440 |
| 5" | 2.22 | $330-$530 | $1,080-$1,800 |
| 6" | 2.67 | $400-$640 | $1,296-$2,160 |
Cost Breakdown for a 12x12 Slab (4 Inches Thick)
- Concrete material (1.78 yd³): $270-$430
- Short-load fee (under 3 yd³): $30-$80
- Site prep (excavation, base, level): $144-$432
- Reinforcement (wire mesh): $50-$95
- Labor (forms, pour, finish): $370-$575
- Total installed: $864-$1,440
Common Uses for a 12x12 Concrete Slab
- Spacious patio (fits a dining table for 6 plus 2-3 chairs around)
- Large hot tub or swim spa pad
- Small detached workshop floor
- Generator/HVAC pad (large units)
- Garden shed (8×10, 8×12, or 10×10 sheds fit with workable margin)
- Outdoor kitchen/grill island base
- Motorcycle storage shed
DIY vs Hire a Contractor
1.78 cubic yards is the upper edge of comfortable DIY. With 2+ experienced helpers, a long Saturday gets it done. Solo or first-timers should hire — placing 4,000+ pounds of concrete in 30 minutes (before it starts setting) is physically demanding and time-pressured.
DIY savings: ~$500-$700 in labor. DIY costs in tool rental (mixer if bagging, finishing tools): $50-$150. Net savings: ~$400-$600.
Frequently Asked Questions
How much concrete for a 12x12 slab?
12 ft × 12 ft × 4 inches = 48 cu ft = 1.78 cubic yards. Add 10% for waste = order 1.96 cubic yards (round to 2). At 5 inches thick, it's 2.22 cubic yards.
What does a 12x12 concrete slab cost in 2026?
Installed: $864-$1,440 (broom finish). DIY material: $310-$480 via ready-mix or $480-$580 in 80-pound bags. Stamped finish adds $864-$1,728 to the installed price.
How many bags of concrete for a 12x12 slab?
At 4 inches thick (1.78 cu yd = 48 cu ft): 60-pound bags (0.45 cu ft each): 107 bags. 80-pound bags (0.6 cu ft each): 80 bags. 90-pound bags (0.675 cu ft each): 72 bags. Ready-mix is typically more cost-effective above 1.5 cubic yards.
Can I park a car on a 12x12 slab?
Yes if 5+ inches thick with rebar (not just mesh). A standard car parking spot is 9×18 ft, so 12×12 is a tight fit — better for storage of a single small car or motorcycle. For comfortable car parking, go 14×20 or larger.
Is 12x12 a standard slab size?
It's a common round-number size for patios, hot tubs, and small workshops. Not a 'standard' that retailers price specifically, but very frequent in residential projects.
What about 12x12 patio with edges or borders?
Add 6-12 inches per side for a finished edge — actual pour becomes 13x13 or 14x14. Decorative borders (stamped or stained) cost $3-$5/linear foot of edge.
Related Sizes & Guides
- 10x12 Concrete Slab — slightly smaller
- Concrete Slab Cost Guide — 2026 pricing
- Concrete Thickness Guide — choose the right depth