Concrete Calculator
Estimate how much concrete you need for a slab, wall, footing or column.
How to Use
- Choose the shape that matches what you're pouring from the options above the form.
- Enter its dimensions and pick whether they're in feet or meters.
- Optionally set Quantity (for multiple identical pours) and a Waste allowance percentage — both default to a safe no-op (1 and 0%) if left as-is.
- The result updates instantly, showing volume in cubic meters, cubic yards and cubic feet.
Formula
- Slab / Wall / Footing
- volume = length × width × thickness
- Column / Footing
- volume = π × (diameter ÷ 2)² × height
- Both
- total = volume × quantity × (1 + waste% ÷ 100)
Worked Example
A 10 ft by 10 ft slab, 6 inches (0.5 ft) thick.
- volume = 10 ft × 10 ft × 0.5 ft = 50 ft³.
- 50 ft³ converted: ≈ 1.4158 m³, ≈ 1.8519 yd³.
Result: 1.4158 m³ (1.8519 yd³, 50 ft³)
About This Tool
What this tool does
This calculator computes the geometric volume of a rectangular slab, wall, or footing, or a circular column or footing, and shows it in cubic meters, cubic yards, and cubic feet.
When to use it
Use it to get a starting estimate of how much concrete a pour will need, before ordering from a supplier or calculating bag counts for a specific mix.
What the result means
The result is the total volume for `quantity` identical pours, after applying any waste allowance you entered, shown in the three units concrete is most commonly ordered or discussed in.
Assumptions & limitations
This tool calculates geometric volume only — it does NOT estimate bag counts, recommend a mix ratio, check PSI/strength requirements, or suggest rebar or reinforcement. Those decisions depend on the specific project, local building code, and engineering judgment; consult a supplier or professional for them. All dimensions must be entered in a single, consistent unit and must be greater than zero. A waste allowance of 0% means no extra margin is added.