What does it mean?
A rebar grade identifies specified material properties, not the diameter or total amount of steel. B500B is a commonly encountered designation associated with a 500 MPa characteristic yield strength and ductility class B within the relevant reinforcement standard. Procurement must also match the applicable standard, certification and designer’s requirements. Grade names are not automatically interchangeable across jurisdictions.
In practice
A drawing calling for 12 mm B500B bars specifies both size and material grade. The weight estimate can use the diameter, but purchasing an apparently similar bar requires confirmation that all specified properties match.
Keep in mind
When preparing an estimate, record the specification reference, units and source of each assumption. Separate the net measured quantity from purchase allowances so changes remain easy to trace. Confirm product dimensions, yields and installation requirements with the supplier. Quantities do not establish structural adequacy or material suitability: use the project’s approved design and details, and seek the responsible designer’s clarification where the specification is incomplete.