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The U.S. Postal Service’s postmark practices, formalized in a December 2025 rule, could lengthen the time between when something is mailed and when it’s postmarked. This distinction is important for tax returns, mail-in ballots, and other time-sensitive documents.
The issue could surface as two deadlines approach: Oct. 15 for taxpayers who received a six-month extension to file their federal income tax returns, and Nov. 3 for voters voting in the midterm elections.
Taxpayers who mail their returns can meet Thursday’s deadline by taking their returns to the post office and having them postmarked. But voters who vote by mail in midterm elections can’t necessarily rely on the same rules.
That’s because, while the IRS typically considers returns filed on the date of the postmark, most states require mail-in ballots to arrive by Election Day, regardless of when they were mailed or postmarked. The postmark indicates the date your mail was processed, but may not be the date you mailed your ballot.
Thirty-five states require election officials to receive mailed absentee ballots on or before election day, according to the National Conference of State Legislatures, a nonpartisan organization that tracks state laws and policies. Fifteen other states (as well as Washington, D.C., Guam, Puerto Rico, and the Virgin Islands) generally allow subsequent arrival (usually within a specified number of days) of ballots postmarked by Election Day.
“Elections are mostly governed by state law, and each state chooses to do things a little differently,” said Katie Owens-Huebler, director of elections and redistricting at NCSL.
Approximately 1.2% of mail-in ballots in 2024 were rejected.
According to the U.S. Election Assistance Commission, nearly 48 million voters have cast absentee ballots in the 2024 presidential election, or about 30% of the 158.2 million total votes cast. The absentee count includes mail-in ballots as well as ballots returned in drop boxes or in person.
According to the commission, about 1.2% of mail-in ballots cast in 2024 were rejected. Of these, 40.7% were rejected because the signature on the return envelope did not match the signature on file or was incomplete, and 10% were rejected because a signature was missing. An additional 17.8% were rejected because they were not received by state deadlines.
These deadlines vary by state. In California, for example, mail-in ballots postmarked by Election Day can arrive up to seven days later and still be counted, according to NCSL. By contrast, Colorado requires mail-in ballots to be received by 7 p.m. on Election Day. Some states are giving military and overseas voters additional time after Election Day for their ballots to arrive.
In a June ruling, the Supreme Court upheld states’ ability to count mail-in ballots received after Election Day, provided they were cast on time and met state deadlines.
Mail your ballot one week before Election Day
Voters should generally be aware that ballots may take longer to arrive at election offices than expected and may not be postmarked the same day they are mailed.
This comes as the U.S. Postal Service is undergoing an overhaul of its operations, which includes fewer pickups at many post offices over time and an increase in travel time for mail to reach regional processing centers where postmarks are applied. As a result, according to Postal Service rules that went into effect in December 2025, post offices can expect longer delays between when mail is shipped and when it’s postmarked.
In practice, this means that some mail does not start moving through the system until at least the day after it is mailed, so postmarks from the day it is mailed do not apply. In some cases, such as on weekends or before holidays, it may take longer for the postmark to be posted, according to the think tank Brookings Institution.
But starting Oct. 24, the Postal Service announced it would take “extraordinary measures,” including additional deliveries to election offices, to speed delivery of mail-in ballots ahead of the Nov. 3 election. Starting Oct. 26, postal workers will manually postmark ballots delivered directly to local election offices or transferred to other election offices via postal hubs, according to a memo from the USPS.
“These things go beyond what the Postal Service does with any other mail,” said Tammy Patrick, chief program officer at the National Association of Election Officials, a nonprofit organization of election officials.
Nevertheless, these measures do not guarantee that your ballot will arrive by your state’s deadline.
For voters mailing in their ballots, “try to mail your ballot one week before the voting deadline,” Patrick said. “If it’s getting close to Election Day and you live in a state that allows postmarking, you can go to any post office and get a handwritten postmark.”
On the other hand, taxpayers who file their returns online can avoid the postmark issue entirely. If you need to mail your return, please ask a postal worker to postmark it manually or send it by certified mail.
