Brazil electoral rules exclude null and blank votes from results

Under Brazilian electoral law established in 1997, null and blank votes do not influence the final outcome of elections. Only valid votes—those cast for specific candidates or parties—are used to determine winners.

In majoritarian elections, a candidate must receive 50% of the valid votes plus one to win in the first round. Because null and blank votes are excluded from this calculation, an election remains valid even if a vast majority of voters choose to cast null or blank ballots. The winners are decided solely by the percentage of valid votes cast.

Historically, blank votes were considered valid and counted toward the winner until the enactment of Law No. 9.504 in September 1997. With the transition to electronic voting machines, the Superior Electoral Court (TSE) standardized the process: a blank vote is cast by pressing the ‘blank’ key, while a null vote is cast by entering an invalid candidate number, such as ‘00’.