Estimate the reinforcement steel (rebar) needed for a footing, column, beam or slab from its concrete volume — a preliminary planning figure for ordering.
Rule-of-thumb reinforcement density by element type — a preliminary ordering estimate, not a bar-bending schedule. The actual quantity depends on span, load and your structural engineer's design.
These are standard preliminary-estimating densities used across the industry when a detailed structural drawing isn't yet available: footings ~75 kg/m³, slabs ~90 kg/m³, columns ~120 kg/m³, beams ~130 kg/m³. Columns and beams carry more steel per cubic meter because they take more concentrated load in a smaller cross-section.
The unit weight of a steel bar in kg per meter is exactly D²/162, where D is the bar diameter in millimeters — a formula derived directly from steel's density (7,850 kg/m³). This calculator uses it to translate your total steel weight into an approximate number of standard 12mm, 12-meter bars, the size and length most commonly stocked by Pakistani steel suppliers.
A real structural drawing specifies exact bar diameters, spacing and cover for every member — which changes the true steel weight substantially. Use this figure to plan a budget and place a preliminary order, then confirm the exact bar-bending schedule with your structural engineer or contractor before final procurement.