What this calculator does
Concrete volume works out cubic metres for a slab, footing or set of posts. Enter your own figures above and the answer updates as you type: nothing is fixed in the code, so the result reflects exactly the numbers you supply.
The formula this calculator evaluates is printed under the tool and explained below, so you can check the working by hand or reuse it in a spreadsheet.
The formula
FormulaVolume = length × width × depth (+ 5–10% allowance); 1 m³ ≈ 2.4 tonnes
The inputs explained
| Field | What to enter |
|---|---|
| Length (m) | A number, measured in m. Starts at 4. |
| Width (m) | A number, measured in m. Starts at 3. |
| Thickness (mm) | A number, measured in mm. Starts at 100. |
| Allowance (%) | A number, measured in %. Starts at 10. |
| Price per m³ delivered ($) | A number, measured in your currency. Starts at 280. |
Worked examples
Every figure in the tables below is produced by this page’s own calculator at build time, so the numbers and the tool always agree. Select any row to load that scenario.
How the answer changes with length
Every other input is held at the calculator’s starting values while length varies. Select any row to load that scenario into the calculator.