Most laws passed by the National Council are simple federal laws, for which a simple majority ("unconditional majority") of the votes cast is sufficient. It is not necessary for all 183 Members of Parliament to be present for the vote. According to Article 31 of the Federal Constitutional Law (in German), it is sufficient if one third of the Members are present. In practice, however, it is customary for almost all Members to be present in the chamber during votes (otherwise there would be random majorities that do not reflect the actual will of the Parliamentary Factions). "Simple majority" means that more than half of the Members present must vote "in favour" – in the event of a tie, a motion is deemed rejected or a question is deemed denied (Section 64(3) GOG-NR). Abstentions are not permitted.
For a simple federal law to be passed, at least 92 of the 183 MPs present must vote in favour. If only one third of the MPs (61) are present, 31 of them would have to vote in favour of the law.