How the Footing Estimate Works
For rectangular footings, the calculator multiplies length × width × depth × number of footings. It then applies the allowance you select. A 5m × 300mm × 400mm footing entered twice has a base volume of 1.20m³; with 10% selected, the planning quantity is 1.32m³.
Separate unequal footings
The count field assumes every footing has the same dimensions. If your plan contains several footing sizes, calculate each group separately and add the final cubic-metre quantities. Measure trenches after excavation where practical because their real dimensions can differ from nominal dimensions.
Use dimensions from a design
This calculator only estimates material quantity. It does not determine footing width, depth, reinforcement, founding material, concrete strength or whether engineering and approval are required. Enter the dimensions specified in the project documentation.
See the complete methodology and source list.