How does postal voting work and how are mail ballots checked?

Postal voting means ballot papers are sent to voters, and usually returned, by post instead of being cast in person. Some places let anyone vote by post on request. Others limit it to people who meet certain criteria, such as being unable to travel to a polling place. Most voters must apply for a postal vote, although some receive one by default. In all-postal voting, every elector receives a ballot paper through the post, not just those who asked for one.

It is used a lot. About 18.5 million voters, 37% of the electorate, voted by post in Germany's 2025 federal election. In the US, about a quarter of ballots, roughly 33 million, were cast by post in 2016, and an estimated 42% of votes were cast by mail in 2020.

Because the voter is not in front of an official, the ballot is checked after it arrives. In many US states the first step is to compare the voter's signature on the outer envelope with signatures on file in the election office. As of 2024, 31 US states conducted signature verification on returned absentee or mail-in ballots. Checks like these are meant to protect against fraud while keeping the ballot secret.

The checks have a cost. As of 2020, about 1% of US postal ballots were rejected, compared with .01% of in-person ballots, where election workers can help verify and assist the voter.

Countries have disagreed about how much risk is acceptable. Australia abolished postal voting in 1910 after claims that it was open to abuse and biased towards rural voters, then restored it in 1918. France banned it in 1975, except in very limited circumstances, because of fears of voter fraud.