Concrete Slab Price Calculator
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Concrete Volume Required:
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Material Cost:
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Labor Cost:
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Estimated Total Price:
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How to Estimate Concrete Slab Costs
Whether you are planning a new driveway, a patio, or a garage floor, understanding the costs involved in a concrete pour is essential for budgeting. The price of a concrete slab is generally determined by two primary factors: the volume of concrete required (measured in cubic yards) and the labor involved in preparation and finishing.
The Slab Calculation Formula
To calculate how much concrete you need, you first find the volume in cubic feet and then convert it to cubic yards. The basic formula is:
Step 1: Length (ft) × Width (ft) × [Thickness (inches) / 12] = Total Cubic Feet
Step 2: Total Cubic Feet / 27 = Total Cubic Yards
Common Slab Thickness Standards
| Project Type | Standard Thickness | Use Case |
|---|---|---|
| Walkways/Patios | 4 Inches | Light foot traffic only |
| Residential Driveways | 5 Inches | Standard passenger vehicles |
| RV Parking/Heavy Loads | 6+ Inches | Heavy trucks and equipment |
Factors That Influence Final Price
- Subgrade Preparation: Leveling the ground and adding a gravel base can add $1 to $2 per square foot.
- Reinforcement: Adding rebar or wire mesh increases structural integrity but adds to material and labor costs.
- Finish Type: A standard "broom finish" is cheapest. Stamped concrete or polished finishes can double or triple the labor rate.
- Site Access: If a concrete truck cannot pull up directly to the pour site, you may need to rent a concrete pump, which typically costs $500–$900 per day.
Example Calculation
Imagine you want to pour a 20′ x 20′ garage slab that is 6 inches thick. Here is how the math works:
- Square Footage: 20 × 20 = 400 sq ft.
- Volume: 400 × 0.5 ft (6 inches) = 200 cubic feet.
- Cubic Yards: 200 / 27 = 7.41 yards.
- Material Cost: 7.41 yards × $130/yard = $963.30.
- Labor Cost: 400 sq ft × $6/sq ft = $2,400.
- Total Estimated Cost: $3,363.30 (excluding base and reinforcement).
Why Include a Waste Factor?
Experienced contractors always order 10% more concrete than the exact measurement. This accounts for variations in the grade (if the ground isn't perfectly flat), spillage, or slight errors in measurement. Running out of concrete halfway through a pour (a "cold joint") can compromise the entire structure.