Update 01
New U.S. Postal Service Rules Could Affect Whether Your Tax Filing Is Considered on Time – Reminder
You may have heard the phrase “timely mailed is timely filed.” Here’s what that really means: under § 7502, if the tax return or payment is postmarked on or before the due date, the IRS will treat it as timely even if it arrives days later.
That same rule applies if you’re filing a petition with the U.S. Tax Court. But here’s the catch: new U.S. Postal Service (USPS) rules could cause the postmark to be later than the day you or the client actually mailed the documents.
And if the postmark is dated after the deadline – even by a day – the filing would be late, and the client could face penalties.
New USPS rules could mean in some local post offices the postmarks may reflect when mail is processed, not when you or the client send it. To protect yourself and the client file or pay electronically when possible, or if mailing near a deadline, go to a post office counter and obtain a dated postmark and proof of mailing.
The USPS adopted new rules governing postmarks, effective December 24, 2025. Instead of reflecting on the date when you or the client drops the mail in a mailbox or hand it to a carrier, a postmark may reflect when the mail is first processed at a USPS facility.
While these changes are intended to improve mail processing efficiency at limited post offices, they may have unintended consequences for taxpayers who rely on the mail to file returns or send payments, depending on how the USPS implements its new procedures.
When the IRS receives a tax form or payment after the due date, the postmark date can be the determining factor of whether the submission is considered timely, and whether late filing or late payment penalties may apply. And the U.S. Tax Court also treats a petition as timely filed if the Tax Court receives it in an envelope bearing a legible USPS postmark dated within the time for timely filing.
When it comes to taxes and deadlines, the importance of making payments and filing returns timely cannot be understated. Filing timely helps taxpayers avoid unnecessary penalties and is critical to preserve their rights.
The date when the USPS first accepts possession of the piece of mail can occur under a variety of circumstances, such as when a letter carrier collects mail from a mailbox or collection box, or when a postal retail associate accepts a piece of mail from a customer at a retail location. Under the new rules, postmarks are applied when mail reaches automated processing, not when USPS first receives it.
The postmark date applied in an originating processing facility is often the same date the USPS first accepted possession of the piece of mail. However, because the USPS has consolidated processing to increase efficiency and reduce costs, the amount of mail where the date of acceptance and the postmark date are different may increase.
The new rules may affect postmarks on mail placed in traditional USPS blue mailboxes, for instance. As a postmark will not be applied until mail reaches an automated sorting facility, the postmark could be one to three days from the date the customer dropped the piece in the mailbox, depending on when the mail is picked up from the blue mailbox and whether the following day is a Sunday or holiday.
For example, a piece of mail that first enters postal possession on a Saturday preceding a Monday holiday may be processed and postmarked on Tuesday – a gap of three days.
One in five taxpayers lives in a rural area, where it is more likely that postmark dates will be affected by this change. One way USPS is seeking to increase efficiency and reduce costs is through reducing trips between local offices and processing facilities from multiple times per day to a single trip per day. Letters and flat-shaped mail that originate more than 50 miles from a USPS regional processing and distribution center may reflect a postmark date one to three days later than the date of mailing.
If you are close to a filing deadline, do not rely on a mailbox alone. One method of ensuring your postmark date is the same as your date of mailing is by using an authorized private delivery service. In addition, there are several options available for taxpayers who want to use the USPS and ensure the postmark date is the same as the date of mailing, and equally important, that they have documentation to prove it. Go to a USPS counter and use:
- Certified Mail;
- Registered Mail; or
- Postage Validation Imprint (special marking indicating postage paid and date accepted).
These options provide proof of the mailing, which can protect the client if there’s ever a question about whether they filed on time. And if the required postage (e.g., stamps) is already on the envelope and not purchased at the time of mailing, a customer can request a manual (local) postmark at any post office for free when sending their mail.
This method ensures the postmark reflects the date of mailing, but keep in mind that requesting a free, manual postmark does not create a document the client can retain as proof of the postmark date. It’s also important to note that a pre-printed label applied prior to mailing, such as a private meter mail stamp or postage from a private, online postage-printing service will not serve as proof of a postmark date.
Whenever possible, filing the return or making a tax payment electronically is the safest way to sidestep any issues with postmarks. The client receives confirmation right away, and they do not have to worry about postmarks or mail delays.
However, some forms, such as Form W-7, Application for IRS Individual Taxpayer Identification Number (and the accompanying return), and Form 706, United States Estate (and Generation-Skipping Transfer) Tax Return, are not eligible for electronically filing.
If mailing one of these paper forms close to the due date, the best practice is to go to a post office counter and make sure the postmark is stamped on the envelope at the same time you place it in USPS custody and that the client obtains a receipt reflecting that date as the postmark date.
