About this calculator
Estimate cubic metres of concrete for a slab with waste allowance.
Measure several points where ground depth varies and use a sensible allowance.
Formula
Volume = length × width × depth in metres.
Example
5m × 3m × 100mm = 1.50m³ before waste.
Accuracy
NUMTX shows the assumptions next to the calculation so you can replace defaults with values that match your situation. For measurements, supplier rates, fees, interest, tax or regulated work, confirm important figures with the appropriate official or professional source.