Brazil electoral systems explained: majority and proportional rules

Brazil utilizes two distinct electoral systems to elect its representatives: the majority system and the proportional system. Under the majority system, used for President, Governors, and Mayors in cities with over 200,000 voters, a candidate must secure an absolute majority—more than 50% of valid votes—to win in the first round. If no candidate achieves this, a second round is held between the top two contenders. Historically, since the 1989 redemocratization, only Fernando Henrique Cardoso has won a presidential election in the first round. In the event of an absolute tie in a second round, the oldest candidate is declared the winner.

For the Senate, a simple majority is sufficient. Conversely, the proportional system is used to elect Federal, State, and District deputies, as well as councilors. This system determines seat distribution based on both individual votes and the total votes received by a party or federation, calculated through the electoral and party quotients. This mechanism explains how candidates with low individual vote counts can still be elected if their party performs strongly overall.

As the 2026 elections approach, political analysts note that high fragmentation among candidates may make a first-round victory difficult, potentially leading to a highly competitive second round.