Concrete Estimate Calculator
0% (Exact)
5% Recommended
10% Safe Margin
Calculation Results
Total Volume: Cubic Yards
Cubic Feet: ft³
80lb Bags: bags
60lb Bags: bags
Estimated Material Cost: $
How to Estimate Concrete for Your Project
Calculating the correct amount of concrete is critical for any construction project, whether you are pouring a new patio, driveway, or footings. Ordering too little leads to cold joints and structural weaknesses, while ordering too much results in wasted money and disposal issues.
Step-by-Step Calculation
- Measure Dimensions: Determine the length and width of your area in feet. If you have extra inches, convert them to decimal feet (e.g., 6 inches = 0.5 feet).
- Determine Thickness: Most residential walkways are 4 inches thick, while driveways meant for heavy vehicles should be 5 to 6 inches thick.
- Calculate Cubic Feet: Multiply Length × Width × Thickness (in feet). For a 4-inch slab, multiply by 0.333.
- Convert to Cubic Yards: Since concrete is sold by the cubic yard, divide your total cubic feet by 27.
Project Examples
- Standard Patio (10′ x 10′ @ 4″): Requires approximately 1.23 cubic yards (including 10% waste).
- Typical Walkway (3′ x 20′ @ 4″): Requires approximately 0.82 cubic yards (including 10% waste).
- Double Driveway (20′ x 20′ @ 6″): Requires approximately 8.15 cubic yards (including 10% waste).
Why the Waste Factor Matters
In the construction industry, it is standard practice to add a 5% to 10% waste factor. This accounts for variations in the subgrade (ground not being perfectly level), form deflection, and spillage during the pour. It is always better to have a small amount left over than to run short when the cement truck is on-site.