About this calculator
Estimate concrete volume and premix bag quantity for a rectangular pour.
Use the bag yield printed by the manufacturer for bag calculations.
Formula
Volume = length × width × depth. Order volume = volume × (1 + waste%).
Example
4m × 3m × 100mm = 1.20m³ 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.