Concrete Calculator — Calculate Concrete Volume & Costs

Concrete Calculator

Calculate the amount of concrete needed for your project. Determine cubic yards, number of bags, and total cost for slabs, footings, columns, and more.

Step 1: Project Dimensions

20 ft
10 ft
4 in

Standard Thickness Guidelines

Driveways: 4-6 inches, Patios: 4 inches, Sidewalks: 4 inches, Foundations: 8-12 inches. Thicker concrete provides more strength but costs more.

Step 2: Materials & Costs

$125
10%

About Waste Factor

Add 5-10% extra for spillage, over-excavation, and uneven subgrade. For complex shapes or inexperienced workers, use 15-20% waste factor.

Concrete Calculation Results

Summary
Project Comparison
Cost Breakdown

Total Concrete Needed

2.47 yd³
For a 20ft × 10ft × 4in slab
Total Cost
$309
Concrete Bags
122 bags
Cubic Feet
66.7 ft³
Cost per Square Foot
$1.55

Project Type Comparison

Project Type Typical Thickness Concrete Needed Estimated Cost

Cost Breakdown

Concrete Calculation Formula

Volume (cubic yards) = Length × Width × (Thickness/12) ÷ 27

To calculate concrete needed: Multiply length (ft) by width (ft) by thickness (in/12 to convert to feet), divide by 27 to get cubic yards. Add waste factor (typically 10%).

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