Every American knows that April 15 is the deadline for submitting tax returns and tax payments to the federal government. Whether you’ve filed already, are preparing to hit send, or are frantically rushing to the Post Office, midnight April 15 is the date to get it done by.
Or is it? If you are making an electronic payment or are getting a physical postmark, recent updates may mean April 15 is too late.
Electronic Payments Made on April 15 May Be Too Late
Federal law (26 U.S.C. § 7502) states that any payments to the IRS mailed by April 15 are timely. This “mailbox” rule can be used by taxpayers who mail checks to the IRS, so long as the paper payment has a postmark before the deadline.
However, no such law exists for electronic payments. Instead, electronic payments are made when the IRS receives them. Although hitting send on an electronic payment gives the illusion of instantaneous payment, electronic payments often take several days to process. The Treasury Department’s Electronic Federal Tax Payment System warns: “Payments using this Web site or our voice response system must be scheduled by 8 p.m. ET the day before the due date to be received timely by the IRS.” The IRS can and will consider a payment late, and apply penalties, if it receives it electronically a few days after April 15.
This is outdated and dumb—the National Taxpayer Advocate correctly observed that an electronic payment made after 8 p.m. on April 14 will be considered late even though the IRS will receive it before a check mailed on April 15 that arrives about a week later and is considered timely. NTU has recommended that the law be updated to include electronic payments made before the deadline, and luckily it’s a provision in the Taxpayer Assistance and Service Act legislation pending now before Congress. But, until that becomes law, make your electronic payments well before the deadline.
Mailed Returns and Payments May Not Be Postmarked on Time
Postmarks may no longer mean the date of mailing, although the Postal Service denies any change in policy. In November 2025, the Postal Service adopted a rule defining postmarks and explaining that postmarks are applied when mail moves through an automated processing center. This may be the same day, or a few days after, mail is received at the counter or collected from a box.
For taxpayers mailing their return (or voters sending in a mail-in ballot), the postmark may be after the deadline if it is turned in but not processed at an automated center for another day or two. The Postal Service argues that this has been current practice for some time, although its expanded use of these facilities under the Regional Transportation Optimization initiative may make same-day postmarks less common now. (The Postal Service also claims that the postmark only exists for internal Postal Service functions, ignoring laws like the federal postmark rule cited above or the 14 states that use the postmark as evidence when a mail ballot was sent that rely heavily on it.)
The Postal Service advises that taxpayers can request a manual postmark at the counter, pay for postage at a machine that prints the date, use registered or certified mail that records the date mailed, or use a private courier service that the IRS has approved for proof of timely filing. The Postal Service could and should direct all employees to apply manual postmarks to all mail received on April 15 and the days leading up to it, but, until it does so, just dropping your tax returns in the box on April 15 may no longer be enough.
The bottom line is that the tax system hasn’t kept up with how Americans actually file and pay. A rule that treats a check drifting through the mail for a week as timely, while penalizing an electronic payment made on April 15, makes little sense. But, until Congress modernizes the law and the Postal Service aligns its postmark practices with common sense, taxpayers should assume the real deadline is earlier than April 15. Pay electronically at least a day in advance, and, if you’re mailing anything, get proof of when it was sent. Caution isn’t overkill, but rather the best way to avoid a penalty.