Concrete Volume and Cost Calculator
Use this calculator to estimate the amount of concrete needed for your project and its approximate cost. This tool is ideal for slabs, footings, patios, and other rectangular or square concrete pours.
Recommended: 5-10% for spillage, uneven subgrade, etc.
Calculation Results:
Enter your project details and click "Calculate Concrete" to see the results.
Understanding Concrete Calculations
Concrete is a fundamental building material, and accurately estimating the quantity needed is crucial for any construction project. Ordering too little can cause delays and extra delivery charges, while ordering too much leads to waste and increased costs.
How the Calculator Works
Our Concrete Volume and Cost Calculator simplifies the process by taking your project's dimensions and providing an estimate in cubic yards, the standard unit for ordering concrete. Here's a breakdown of the calculation:
- Volume in Cubic Feet: The calculator first determines the volume of your slab or footing in cubic feet. This is done by multiplying the Length (in feet) by the Width (in feet) by the Thickness (converted from inches to feet).
- Conversion to Cubic Yards: Since concrete is typically sold by the cubic yard, the calculated volume in cubic feet is then divided by 27 (because 1 cubic yard = 3 feet x 3 feet x 3 feet = 27 cubic feet).
- Waste Factor: It's common practice to add a "waste factor" to your concrete order. This accounts for spillage, uneven subgrades, minor miscalculations, or simply having a little extra on hand. A typical waste factor ranges from 5% to 10%. Our calculator allows you to adjust this percentage.
- Estimated Cost: Finally, the calculator multiplies the adjusted volume (including the waste factor) by your estimated cost per cubic yard to give you a total project cost.
Formula Used:
Volume (cubic feet) = Length (feet) × Width (feet) × (Thickness (inches) / 12)
Volume (cubic yards) = Volume (cubic feet) / 27
Adjusted Volume (cubic yards) = Volume (cubic yards) × (1 + (Waste Factor / 100))
Total Cost = Adjusted Volume (cubic yards) × Cost per Cubic Yard
Tips for Ordering Concrete:
- Measure Accurately: Double-check all your measurements. Even small errors can lead to significant differences in concrete volume.
- Consider Subgrade: If your subgrade (the ground beneath the concrete) is uneven or soft, you might need to increase your waste factor slightly.
- Account for Forms: Ensure your forms are securely built and level to prevent blowouts or uneven pours.
- Talk to Your Supplier: Always confirm the minimum order size and delivery charges with your local concrete supplier. They can also offer advice on specific mixes for your project.
- Round Up: It's generally better to have a little too much concrete than not enough. Most suppliers will round up to the nearest quarter or half yard.
Example Calculation:
Let's say you're pouring a patio that is 20 feet long, 10 feet wide, and 4 inches thick. You estimate the concrete cost at $120 per cubic yard and want to add a 10% waste factor.
- Length: 20 feet
- Width: 10 feet
- Thickness: 4 inches = 4/12 = 0.3333 feet
- Volume in Cubic Feet: 20 ft × 10 ft × 0.3333 ft = 66.66 cubic feet
- Volume in Cubic Yards (raw): 66.66 cubic feet / 27 = 2.469 cubic yards
- Adjusted Volume (with 10% waste): 2.469 cubic yards × (1 + 0.10) = 2.469 × 1.10 = 2.716 cubic yards
- Total Estimated Cost: 2.716 cubic yards × $120/cubic yard = $325.92
Using the calculator with these values will give you approximately 2.72 cubic yards of concrete and an estimated cost of $325.92.