The weight of rebar in a structure or module is the total mass in kilograms or pounds of all steel reinforcing bars in the concrete belonging to that object. This includes all reinforced concrete which is architecturally integral, whether it is load-bearing or not. It includes elements both above ground and below ground, including the foundations.

A finished building is never weighed. Figures of this kind come from the bill of quantities or the structural drawings, so they record what was specified, and a value for a building still going up is a plan rather than a measurement.

The material counts only where it does structural work. Reinforcement in a non-structural screed, cladding hung on a frame and decorative timber are outside these fields even though they are the same material.

Where a structure was extended or partly rebuilt, the figure belongs to whichever scope the source measured. A weight for the original building and one for the building today are different numbers.