Concrete Calculator
Concrete Calculator
Calculate the concrete you need from your project dimensions. This free concrete calculator estimates concrete volume and order quantity for slabs, pads, footings, walls, round columns, post holes, circular pads, hollow tubes, trapezoidal footings and stepped concrete.
How to use the concrete calculator
- Select the concrete shape you want to calculate.
- Choose your measurement unit: metres, centimetres, millimetres, feet or inches.
- Enter the required dimensions and quantity.
- Set a waste / overage allowance if needed.
- Choose an optional material-cost method if you want a cost estimate.
- Select Calculate to see the result.
The calculator converts the entered dimensions to metres internally and calculates the geometric concrete volume. The result includes the estimated order quantity, cubic yards, cubic feet and litres. Depending on the selected cost option, it can also show bag quantities and estimated material cost.
Concrete calculation formulas
The calculator uses the appropriate geometric formula for the selected shape. For example, a rectangular slab uses:
Volume = Length × Width × Thickness
A round column or circular section uses:
Volume = π × (Diameter ÷ 2)² × Height × Quantity
For an allowance:
Order quantity = Concrete volume × (1 + Waste ÷ 100)
You can select Show Formulas in the results section to see the formulas used for your specific calculation.
Results and PDF report
After calculation, the results show the concrete order quantity in m³, together with cubic yards, cubic feet and litres. Where applicable, the calculator also provides bag quantities and an estimated material cost.
You can also download a PDF calculation report containing the entered inputs, calculation results and formulas used.
Frequently Asked Questions
What does a concrete calculator calculate?
It estimates the concrete volume and order quantity required from the dimensions and quantity entered for the selected concrete shape.
How is concrete volume calculated?
The calculator uses the appropriate geometric formula for the selected shape, such as length × width × thickness for rectangular concrete sections and π × r² × height for cylindrical sections.
Why is waste or overage added?
A selected waste allowance increases the calculated order quantity to account for ordering and placement uncertainty. It is not a structural design factor.
Can I download the calculation?
Yes. After calculating, you can download a PDF report containing the user inputs, results and formulas used.
Important note
This calculator performs mathematical quantity and volume calculations based on the inputs entered by the user. Waste or overage is an ordering allowance, not a structural-design factor. Material-cost and nominal mix estimates depend on the assumptions, supplier information and values entered.
Always cross-check the calculated quantity against your project drawings, actual site measurements, specifications, product data and supplier requirements before ordering materials or making construction decisions. The user is responsible for verifying the inputs and determining whether the calculated result is appropriate for the intended project. This calculator does not replace structural engineering, professional construction advice, project specifications or applicable building codes.