Construction/ CALCULATOR
Calculate geometric concrete volume and a separate ordering allowance.
Add non-overlapping rectangular sections of the same concrete mix. For a thickened edge, enter only its additional depth below the slab already counted. This worksheet is separate from the single-section calculator above.
Entries stay in this tab. Export CSV to keep them before closing or reloading; the existing saved calculations are not changed.
At most 20 sections per worksheet.Initial values are examples. Totals sum unrounded sections; screen rounding is not supplier rounding.
Illustrative quantities, not a ready-to-place order. Allowance is not strength; confirm supplier rounding, concrete specification and structural design separately.
FROM ESTIMATE TO ACTION
Enter length and width in metres and thickness in millimetres: 120 means 120 mm, not 0.120 m. For different thicknesses, calculate non-overlapping sections separately and add their net volumes. Add only the extra volume of thickened edges below the slab already counted.
The allowance covers quantity uncertainty and losses, not strength. Enter 7 for 7%, not 0.07; the example is not a recommended rate. Check measured base levels and discuss placement losses with the contractor. On a 32 m² slab, 10 mm of extra thickness needs 0.32 m³ before any allowance.
Displayed rounding is not the supplier’s order increment. Agree the volume and mix required by the project, delivery access, unloading method and curing plan with the supplier and contractor. This quantity calculation does not design slab thickness or reinforcement, or determine strength or when loading is safe.