Which steel design standard should I use? NBR 8800, AISC 360, or Eurocode 3?

Use the standard your project is legally required to follow — usually based on the country where the structure is built. Brazil: NBR 8800 (hot-rolled) + NBR 14762 (cold-formed). USA: AISC 360 + AISI S100. Europe: Eurocode 3 (EN 1993-1-1 and its national annexes). India: IS 800. Australia: AS 4100. Canada: CSA S16. These codes produce similar results for common cases but differ in load factors, resistance factors, stability curves, and serviceability limits. CalcSteel supports 41 design standards and lets you pick the one that matches your jurisdiction — the verification report will reference the specific code clauses used for each check.