Free Concrete Calculator - Volume & Cost Calculator
Calculate concrete volume, bags needed, and total cost for your construction project. Get accurate estimates for slabs, driveways, sidewalks, and more with our free online concrete calculator.
Concrete Volume Calculator
Calculation Results
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How to Use This Concrete Calculator
Step 1: Choose Your Project Shape
Select whether your project is rectangular, circular, or triangular. This determines which measurements you'll need to provide.
Step 2: Enter Dimensions
Input the required measurements based on your selected shape. Ensure all measurements are accurate for the best results.
Step 3: Specify Depth/Thickness
Enter the thickness of your concrete slab. Common depths are 4 inches for sidewalks and 6 inches for driveways.
Step 4: Select Concrete Type and Cost
Choose your concrete type and enter the local cost per cubic yard. This helps calculate accurate material costs.
Step 5: Calculate and Review
Click calculate to get volume requirements, number of bags needed, and total project cost including waste factor.
Concrete Calculation Formula
Understanding the math behind concrete calculations helps ensure accuracy in your projects:
Volume = Length × Width × Depth
Circular:
Volume = π × (Diameter/2)² × Depth
Triangle:
Volume = (Base × Height × Depth) / 2
To convert from cubic feet to cubic yards, divide by 27. Always add a waste factor of 5-15% to account for spillage, irregular surfaces, and over-excavation.
Calculation Steps
Example: 10' × 12' × 4" Concrete Slab
- Convert depth to feet: 4" ÷ 12 = 0.33 feet
- Calculate volume: 10 × 12 × 0.33 = 40 cubic feet
- Convert to cubic yards: 40 ÷ 27 = 1.48 cubic yards
- Add 10% waste: 1.48 × 1.10 = 1.63 cubic yards
- Calculate bags needed: 1.63 × 45 = 73 bags (80 lb bags)
About This Concrete Calculator
Our concrete calculator is designed to help contractors, DIY enthusiasts, and homeowners accurately estimate concrete requirements for various construction projects. Whether you're planning a driveway, sidewalk, patio, or foundation, this tool provides precise calculations for:
- Total concrete volume needed in cubic yards or cubic meters
- Number of concrete bags required (80 lb and 60 lb options)
- Total material cost estimation
- Weight calculations for transportation planning
- Waste factor inclusion for realistic project planning
The calculator supports multiple project shapes and measurement units, making it versatile for any concrete project size.
Use Cases & Applications
Residential Projects
- Driveways and parking areas
- Sidewalks and walkways
- Patios and outdoor living spaces
- Garage floors and workshops
- Pool decks and surrounds
Commercial & Industrial
- Building foundations
- Warehouse floors
- Parking lots and loading docks
- Curbs and barriers
- Decorative concrete features
Concrete Types & Applications
Standard Concrete (3000-4000 PSI)
Most common for residential driveways, sidewalks, and patios. Good balance of strength and cost.
High-Strength Concrete (4000+ PSI)
Used for heavy-duty applications, commercial floors, and structural foundations.
Fiber-Reinforced Concrete
Contains fibers for added crack resistance, ideal for thin slabs and high-traffic areas.
Lightweight Concrete
Reduced weight for specialized applications, rooftop decks, and renovation projects.
Frequently Asked Questions
To calculate concrete volume, multiply length × width × height for rectangular areas. For circular areas, use π × radius² × height. Convert the result from cubic feet to cubic yards by dividing by 27.
A standard 80-pound bag of concrete covers approximately 0.6 cubic feet or about 45 bags per cubic yard. A 60-pound bag covers about 0.45 cubic feet or 60 bags per cubic yard. Our calculator automatically determines the number of bags based on your project volume.
Concrete costs vary by location and type, typically ranging from $100-$150 per cubic yard for standard concrete, including delivery. High-strength or specialty concrete may cost $150-$200 per cubic yard. Always get local quotes for accurate pricing.
A waste factor accounts for spillage, over-excavation, irregular surfaces, and measurement variations. We recommend 10-15% for most projects. This ensures you have enough concrete to complete your project without running short.
Thickness depends on the application: 4 inches for sidewalks and light-duty slabs, 5-6 inches for driveways and heavy residential use, 6-8 inches for commercial applications, and 8+ inches for heavy vehicle traffic or structural foundations.
For small projects (under 1 cubic yard), bagged concrete is cost-effective. For larger projects, ready-mix concrete is more efficient and ensures consistent quality. Consider factors like accessibility, time constraints, and equipment availability when deciding.