To file Form 8802, the application for U.S. residency certification, send a completed and signed form to the IRS in Philadelphia along with the user fee — $85 for individuals or $185 for other applicants — at least 45 days before you need Form 6166. You can pay online through Pay.gov and submit by mail or fax, or mail a check with the paper form. Since September 2025, individuals also have an online filing option through the IRS Digital Adaptive Mobile Forms platform.
What to Gather Before You Start
The form itself is short, but the IRS verifies everything you put on it against its own records, so accuracy on the inputs matters more than speed. Have these ready:
- Your Taxpayer Identification Number — an SSN for individuals, an EIN for entities.
- The treaty country or countries where you’ll present Form 6166.
- The tax year or years you need certified. One application can cover the current year, prior years, or both.
- Your most recent U.S. tax return. The IRS checks your filing history as part of the review.
- A residency statement if you haven’t yet filed the return for the year you’re requesting. It must document your U.S. residency status and explain the basis for the claim.
If you’re a single-member LLC treated as a disregarded entity, don’t file in the LLC’s name. The application goes in the name and TIN of the sole owner, because that’s whose residency the IRS certifies.
The User Fee
Individuals pay $85. Every other applicant — corporations, partnerships, trusts, estates, exempt organizations, employee benefit plans — pays $185. The fee is per Form 8802, not per country or per year, so listing multiple treaty countries and multiple years on one application doesn’t multiply the cost. It’s also nonrefundable. Sending the wrong amount gets the application returned, and the fee isn’t applied until it matches what you owe.
The amounts were set by Revenue Procedure 2018-50 and have not changed.
How to Submit the Form
There are three routes, and the right one depends on who you are and how you want to pay.
Online Filing (Individuals Only)
As of September 2025, individual applicants can complete and submit Form 8802 through the IRS Digital Adaptive Mobile Forms platform. Business entities cannot use this option yet. You still pay the user fee separately through Pay.gov by searching for “IRS Certs.”
Electronic Payment Plus Mail or Fax
Anyone can pay the user fee at Pay.gov (“IRS Certs”) by direct debit, debit card, or credit card. Once payment clears, write the confirmation number on your Form 8802 and send the signed form with attachments to the IRS. Mail goes to:
Internal Revenue Service, US Residency Certification, Philadelphia, PA 19255-0625.
For private delivery services, use 2970 Market Street, BLN# 3-E08.123, Philadelphia, PA 19104-5016.
Fax numbers are 877-824-9110 (toll-free within the U.S.) or 304-707-9792 (inside or outside the U.S.).
Check or Money Order
If you’d rather pay by check or money order, make it payable to the U.S. Treasury and send the payment, signed form, and all attachments together to the Philadelphia mailing address. The IRS processes payment and application as one package, so don’t split them.
When You Can File
The timing rules catch a lot of people. Two things to know.
First, the IRS won’t accept a current-year application before December 1 of the prior year. For a 2026 certification, the earliest postmark is December 1, 2025. Anything earlier gets returned unopened.
Second, the IRS asks for at least 45 days to process, and that’s a floor. Busy stretches can push it to two months or more. Foreign withholding happens on its own schedule regardless of whether your certification is in flight, so treat 45 days as the bare minimum and file earlier when you can.
Prior-year certifications can be filed any time, provided you’ve filed the return for that year or can document your residency for it.
Authorizing Someone Else to Receive Form 6166
If you want a tax professional, corporate office, or custodian to receive the certification and handle correspondence, you have two ways to set that up.
The simpler route is line 3b on Form 8802. Naming a third-party appointee there authorizes the IRS to communicate with that person and send Form 6166 to the address you list. If the appointee is an entity, identify an individual at the entity who can answer questions about your application.
If you need someone to actually sign Form 8802 or represent you before the IRS, attach Form 2848 (Power of Attorney). If you only need the IRS to share tax information with a third party, Form 8821 (Tax Information Authorization) is enough. In either case, write “See attached authorization” on line 3b.
After You File
The IRS verifies your identity, TIN, and filing history, then mails Form 6166 to you or your designated third party. If they anticipate a delay, they’ll contact you within 30 days. If something is off — a mismatched TIN, missing documentation, an unfiled return for the year requested — you’ll get a mailed request for clarification. Respond fast, because any delay on your end effectively restarts the clock.
The mistakes that stall applications are almost all preventable:
- A typo in the SSN or EIN, or the wrong tax year listed, causing IRS verification to fail.
- The wrong user fee amount — $85 sent by an entity that owes $185, or the reverse.
- No residency statement attached when the return for the requested year hasn’t been filed.
- Filing too close to a foreign deadline, leaving no room for the IRS to process or ask follow-up questions.
Requesting More Certifications Later
Once you have Form 6166 and you need certifications for additional countries or years, don’t start over. Form 8802 has an “Additional Request” checkbox for applicants already approved. Checking it tells the IRS your information is on file, which speeds the review. You still pay the user fee for each new Form 8802.
The shortcut only works if nothing meaningful has changed — same entity, same TIN, same residency basis. If anything has changed, file a fresh application and leave the box unchecked.