You can use a PO box on your tax return, but only if the post office doesn’t deliver mail to your street address. That’s the instruction the IRS repeats across Form 1040, Form 8822, and its business filings: a PO box is a substitute for a street address when home delivery isn’t available, not a matter of preference. If you list a PO box anyway, your return will still process. The real problem shows up later, because the address on your most recent return becomes where the IRS sends everything, including notices with hard legal deadlines.
What the IRS Rule Actually Says
The language is consistent across IRS forms: enter your PO box number instead of your street address only if your post office does not deliver mail to your street address. Form 8822 states this directly, and the same instruction carries through to Form 1040 and other filings.1Internal Revenue Service. Form 8822 – Change of Address
In practice, the IRS won’t reject a return that lists a PO box when you also have home delivery. Processing proceeds normally. But the guidance treats a PO box as an answer to a specific problem: rural addresses without USPS delivery, locations with documented mail theft, or physical addresses the post office simply doesn’t serve. If one of those describes you, a PO box is the right entry and the IRS expects it.
Where a PO Box Doesn’t Work
Some tax-related filings distinguish a mailing address from a physical location, and a PO box can’t cover both.
Form SS-4 for an EIN
The application for an Employer Identification Number has two separate address lines. Line 4a takes a mailing address and can be a PO box. Line 5a asks for a street address and specifically instructs applicants not to enter a PO box.2Internal Revenue Service. Form SS-4 (Rev. December 2025) The IRS wants to know where the business physically operates. If your mailing and street addresses are the same, you leave line 5a blank.
FBAR Filings
If you file a Report of Foreign Bank and Financial Accounts with FinCEN, the standard is stricter than a 1040. An individual living in the United States must provide the street address of their U.S. residence. A non-street address such as a PO box is allowed only when no other street address is available.3Financial Crimes Enforcement Network. FBAR Line Item Filing Instructions Taxpayers with foreign accounts need a physical address on file regardless of what they use on their return.
A Commercial Mailbox Isn’t a PO Box
A mailbox rented from a provider like The UPS Store gives you a street address rather than a PO box number. To the IRS it reads like any other physical address, so it sidesteps the PO box restriction on forms like SS-4. That’s useful if you move often or need a stable mailing point but can’t use a PO box. Keep in mind a commercial mailbox is still a mailing address; it doesn’t establish state residency or a principal place of business.
The Bigger Risk: Missing an IRS Notice
The address on your most recent return becomes your “last known address” for IRS purposes, and that has real legal weight. When the IRS determines you owe additional tax, federal law requires it to send a statutory notice of deficiency to your last known address by certified mail. If the notice goes to that address, it’s legally valid whether you actually receive it.4Office of the Law Revision Counsel. 26 U.S. Code 6212 – Notice of Deficiency
The notice starts a 90-day clock to petition the U.S. Tax Court, or 150 days if you live outside the country. Neither the IRS nor anyone else can extend that deadline. Miss it because the notice sat in a PO box you stopped checking, or one that expired, and you lose your right to challenge the proposed tax in Tax Court before paying it.5Taxpayer Advocate Service. 90-Day Notice of Deficiency Audit reconsideration is still available after the fact, but it’s slower and gives you less leverage.
This is the practical case against a PO box for anyone who has a choice. Mail to a home address is hard to ignore. A PO box only works if you check it. If your IRS correspondence goes to one, treat it like a bank account: don’t let it lapse, and open it regularly.
Updating Your Address With the IRS
If your address changes, whether you’re moving to a PO box, moving off of one, or just relocating, notify the IRS directly. A USPS change of address doesn’t reliably update IRS records, and not every post office forwards government checks even when a forwarding order is on file.6USPS. Mailing Your Tax Return
- Form 8822 is the standard change of address form for individual filers, covering income, gift, and estate tax returns. Processing takes four to six weeks.7Internal Revenue Service. About Form 8822, Change of Address
- Form 8822-B is the version for businesses and other entities with an EIN. It also covers changes to the responsible party, which must be reported within 60 days.8Internal Revenue Service. About Form 8822-B, Change of Address or Responsible Party – Business
- A signed written statement mailed to the IRS with your full name, old address, new address, and SSN or EIN also works. Send it to the address where you filed your last return.9Internal Revenue Service. Address Changes
- You can also call the IRS or visit a local office. Have identifying information ready.
- Filing your next return with the new address updates your records eventually, but it’s the slowest option. Use one of the others if the next return is months away.
Protecting Your Refund
The cleanest way to keep an address issue from turning into a refund issue is to skip the paper check. The IRS treats direct deposit as the fastest and most secure way to receive a refund, with no risk of the check being stolen from a mailbox, sent to an old address, or lost in transit.10Internal Revenue Service. Direct Deposit Is the Best Way to Get a Federal Tax Refund The account should be in your name or your spouse’s.
If a paper check goes to the wrong address, you can start a refund trace through the “Where’s My Refund” tool, by calling 800-829-1954, or by filing Form 3911. If the check hasn’t been cashed, the IRS cancels it and reissues. If it has, the Bureau of the Fiscal Service investigates.11Internal Revenue Service. Refund Inquiries Joint filers can’t use the automated trace and need to call or mail Form 3911.
Filing From Outside the United States
U.S. citizens and resident aliens abroad can list a foreign address on their return. Form 8822 has dedicated fields for the country name, province, and postal code, and the IRS instructs you to spell out the country in full and follow its own postal code format.1Internal Revenue Service. Form 8822 – Change of Address
Where you send the return changes too. Filers living in a foreign country, using an APO or FPO address, or claiming the foreign earned income exclusion on Form 2555 use specific IRS addresses instead of the standard ones. Returns with refunds due go to the IRS center in Austin, Texas; returns with payments enclosed go to a PO box in Charlotte, North Carolina.12Internal Revenue Service. U.S. Citizens and Resident Aliens Abroad – Where and When to File and Pay Many expats maintain a U.S. virtual mailbox to keep a domestic address on file for IRS correspondence. That address works for mail, but it doesn’t establish or change state tax residency.