Columns and footings
Column concrete volume is width × depth × height × number of columns. Steel for columns is estimated at a typical 150 kg per cubic metre — higher than slabs, because columns are reinforcement-dense, carrying both vertical load and the main longitudinal bars plus ties. As with all elements here, the material split uses the chosen grade and the 1.54 dry-volume factor described on the method page.
For isolated footings, switch the element to "footing" inside the BOQ estimator, where footings use a lower ~60 kg/m³ steel estimate that reflects their typical mat reinforcement. Footing volume is length × width × depth × count.
Sizing columns and footings
Column sizes in Indian residential construction commonly start at 230×230 mm (9"×9") for single-storey work and 230×300 mm or larger for multi-storey frames, but the right size is a structural-design decision based on the load coming down from the floors above, the column's unsupported height and the concrete grade. Footing dimensions in turn depend on that column load and the safe bearing capacity of your soil — a weaker soil needs a wider footing to spread the same load.
Why columns use more cement and steel
Columns are usually cast in a richer grade (M20 or higher) and packed with steel because they are compression members whose failure is sudden and catastrophic — unlike a beam, which tends to warn by deflecting first. That is why the steel estimate here is deliberately higher for columns than for slabs or footings, and why you should never under-design them off a quick estimate.