Concrete Slab Calculator
Coverage Table (for Thickness 3" to 30")
| Thickness (inches) | Concrete Volume (ft³) | 60lb Bags Needed |
|---|
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Steps to Calculate the Concrete Requirements
The Concrete Slab Calculator follows these steps to determine the required volume and number of 60lb cement bags:
1️⃣ Get User Input
Users enter:
- Shape (Square, Rectangle, or Circle)
- Length & Width (for Square/Rectangle) OR Diameter (for Circle)
- Thickness (in inches, converted to feet)
2️⃣ Calculate Concrete Volume (Cubic Feet)
Concrete volume depends on shape:
- Square / Rectangle:
Volume = Length × Width × Thickness (in feet) - Circle:
Volume = 3.1416 × (Diameter ÷ 2)² × Thickness (in feet)
Where:
- Thickness in feet = Thickness in inches ÷ 12
- Pi = 3.1416
3️⃣ Determine Number of 60lb Bags Required
One 60lb bag of concrete mix covers 0.45 cubic feet.
Number of Bags = Total Volume (in cubic feet) ÷ 0.45
👉 Round up to ensure full coverage.
4️⃣ Generate Coverage Table for Different Thicknesses (3 to 30 inches)
For each thickness (from 3 to 30 inches in 1-inch increments):
- Convert thickness to feet
- Calculate volume using formulas from Step 2
- Calculate number of 60lb bags using Step 3
5️⃣ Display Results
- Concrete Volume (cubic feet)
- Total 60lb Bags Needed
- Table of Results for Various Thicknesses
📌 Example Calculation
User Input:
- Shape: Rectangle
- Length: 10 ft
- Width: 5 ft
- Thickness: 6 inches
Step-by-Step Calculation:
- Convert thickness: 6 inches → 6 ÷ 12 = 0.5 feet
- Calculate Volume: 10 × 5 × 0.5 = 25 cubic feet
- Calculate Bags Needed: 25 ÷ 0.45 = 55.56 → Round Up to 56 Bags
Final Output:
✔ Concrete Volume: 25 ft³
✔ 60lb Bags Needed: 56