The average early voting time period is 22 days before an election; however, the voting period is different in each state. Early voting is allowed in 33 states plus the District of Columbia, while all states have some sort of absentee voting.
Early and absentee voting allows people who are unable to vote on election day to place their vote before the day of the election. All states allow absentee voting, but some require a valid excuse. Twenty-seven states have "no-excuse" early voting, in which any registered voter is allowed to cast an absentee ballot without being required to give a reason as to why she can't vote on election day.