Concrete Slab Cost Calculator
Estimate concrete slab cost per square foot for patios and floors.
Concrete Slab Cost
What This Calculator Does
The Concrete Slab Cost Calculator estimates the cost of pouring a concrete slab based on size, thickness, and 2026 US national average contractor rates. Enter the slab length, width, and thickness to get a cost range for materials, labor, and total installation.
Concrete slabs are the foundation for patios, garages, sheds, driveways, and basements. The cost depends primarily on slab thickness (4-inch standard, 6-inch for driveways, 8-inch for heavy loads), reinforcement (wire mesh vs rebar), and finishing requirements.
How to Use
- Measure the slab length and width in feet.
- Select the slab thickness - 4 inches (standard), 5 inches, or 6 inches (driveway).
- Select the finish type - broom finish (standard) or smooth trowel (garage/shed floor).
- Click "Calculate" to see the total cost estimates.
- Add $200-$800 for concrete removal if replacing an existing slab.
How to Calculate Concrete Slab Cost
Concrete slab cost is calculated by combining material costs, labor, and optional features:
- Calculate area. Length x Width = Square footage of the slab.
- Determine concrete volume. Convert slab thickness to feet and multiply: (Area x Thickness in ft) / 27 = Cubic yards.
- Material cost. Concrete is $130-$200 per cubic yard delivered. A 4-inch slab needs approximately 1.23 cu yd per 100 sq ft.
- Labor cost. Form setup, pouring, finishing, and curing: $3-$6 per sq ft depending on complexity and finish type.
- Additional materials. Gravel base ($1-$2 per sq ft), reinforcement ($0.10-$1.50 per sq ft), control joints ($0.50-$1.50 per linear ft).
Total cost = Concrete material + Labor + Base prep + Reinforcement + Finishing. Costs vary regionally - typically 20-30% higher in the Northeast and West Coast, 10-20% lower in the South and Midwest.
Practical Measurement Tips
- Subgrade prep is critical. The ground under the slab must be properly graded, compacted, and drained. A 4-6 inch compacted gravel base prevents cracking from soil movement and frost heave. Never pour concrete directly on dirt.
- Control joints. Cut control joints every 8-12 ft (depth = 1/4 of slab thickness) within 4-12 hours of pouring to control cracking. Uncontrolled cracks look worse than control joints.
- Vapor barrier. Install a 6-mil poly vapor barrier under interior slabs (garages, basements) to prevent moisture migration through the slab. Cost: $0.05-$0.10 per sq ft.
- Get multiple quotes. Concrete prices vary significantly between contractors. Get at least 3 quotes and compare the full scope - not just the per-yard concrete price. Some contractors include gravel base and reinforcement; others charge extra.
- Seasonal pricing. Spring and fall are peak concrete season - expect 10-20% higher prices. Winter pours may need heated concrete and blankets (add 15-25%). Late fall is often the best time for competitive pricing.
Worked Examples
Standard Patio Slab
A 16 x 20 ft patio (320 sq ft) at 4 inches thick with broom finish.
- →Area: 16 ft x 20 ft = 320 sq ft.
- →Concrete volume: (320 x 0.33) / 27 = 3.9 cu yd.
- →Concrete material: 3.9 x $150 = $585.
- →Gravel base (4 in): 320 x $1.50 = $480.
- →Wire mesh reinforcement: 320 x $0.15 = $48.
- →Labor (form, pour, finish): 320 x $4 = $1,280.
- →Total estimated cost: $585 + $480 + $48 + $1,280 = $2,393.
- →Cost per sq ft: $2,393 / 320 = $7.48/sq ft.
Result: Estimated $2,200-$2,600 (range: $6.90-$8.10/sq ft) for a 320 sq ft patio.
A 320 sq ft patio is well below the 10-yard truck minimum. Expect a short-load fee of $100-$250 or a minimum charge equivalent to 3-4 cubic yards.
Two-Car Garage Slab
A 22 x 24 ft garage (528 sq ft) at 5 inches thick with smooth trowel finish and rebar reinforcement.
- →Area: 22 ft x 24 ft = 528 sq ft.
- →Concrete volume: (528 x 0.417) / 27 = 8.15 cu yd.
- →Concrete material: 8.15 x $160 (4,000 PSI) = $1,304.
- →Gravel base (6 in): 528 x $2 = $1,056.
- →Rebar reinforcement (#4 at 18 in): 528 x $0.80 = $422.
- →Labor and finishing: 528 x $5.50 = $2,904.
- →Vapor barrier: 528 x $0.08 = $42.
- →Total estimated cost: $1,304 + $1,056 + $422 + $2,904 + $42 = $5,728.
- →Cost per sq ft: $5,728 / 528 = $10.85/sq ft.
Result: Estimated $5,300-$6,300 (range: $10-$12/sq ft) for a 528 sq ft garage slab.
Garage slabs require 4,000-4,500 PSI concrete, #4 rebar at 12-18 inches OC, and a smooth trowel finish for an epoxy coating. Add $300-$600 if you want a thicker thickened edge for the overhead door.
Reference Table
| Slab Size | 4" Thick | 5" Thick | 6" Thick (Driveway) | Includes |
|---|---|---|---|---|
| 10x10 ft (100 sq ft) | $500-$1,000 | $600-$1,200 | $700-$1,400 | Gravel base, mesh, finish |
| 20x20 ft (400 sq ft) | $2,000-$4,000 | $2,400-$4,800 | $2,800-$5,600 | Gravel base, mesh, finish |
| 24x24 ft (576 sq ft) | $2,880-$5,760 | $3,456-$6,912 | $4,032-$8,064 | Gravel base, rebar, finish |
| 30x40 ft (1,200 sq ft) | $6,000-$12,000 | $7,200-$14,400 | $8,400-$16,800 | Gravel base, rebar, finish |
How We Calculate
Cost Components
The cost estimate combines five major components: (1) concrete material at $130-$200 per cubic yard, (2) subgrade preparation including gravel base at $1-$2 per sq ft, (3) reinforcement (wire mesh or rebar), (4) labor for forming, pouring, finishing, and curing, and (5) surface finishing (broom or trowel).
Regional Variations
Costs shown are national averages for 2026. Regional adjustments: Northeast +20%, West Coast +15-25%, Midwest -5%, South -10-15%, Southwest -5%. Urban areas are typically 10-20% more expensive than rural areas for the same slab due to higher labor costs and material delivery fees.
Important Disclaimer
These are planning estimates based on national averages. Actual costs vary by location, contractor, site accessibility, soil conditions, and current material prices. Always obtain at least three itemized quotes from licensed concrete contractors before proceeding. The estimates do not include permits, engineering fees, or site-specific preparation needs such as tree removal or soil stabilization.
References and Data Sources
RSMeans - Residential Cost Data 2026
The standard reference for construction cost estimating in North America. RSMeans publishes annual cost data for concrete, labor, and materials by region, which forms the basis for the national average cost ranges used in this calculator.
ACI 332 - Residential Concrete Home Foundation Walls
American Concrete Institute standard for residential concrete construction, including minimum slab thickness requirements, reinforcement specifications, and construction joint placement. Slab design recommendations in the worked examples reference ACI 332 guidelines.
NAHB - National Association of Home Builders Construction Cost Survey
Annual survey of residential construction costs across US metropolitan areas. Regional cost variation indices used in this calculator are based on NAHB published data for concrete slab construction.
All references are used for general estimation guidance only. BuildCalcHub does not claim certification, endorsement, or partnership with any listed organization. Always consult a licensed professional for your specific project requirements.
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