An IRS CAF number lookup goes one of two ways depending on who you are. If you’re a tax professional trying to recover your own nine-digit Centralized Authorization File number, call the IRS Practitioner Priority Service at 866-860-4259 or sign in to your Tax Pro Account.1Internal Revenue Service. What Is a CAF Number If you’re a taxpayer trying to see which representatives currently have authorization on your account, sign in to your IRS Online Account.2Internal Revenue Service. Power of Attorney and Other Authorizations Either way, you don’t need to file anything to look up what already exists.
What a CAF Number Actually Is
The Centralized Authorization File is the IRS database that tracks third-party authorizations. When a tax professional files their first Form 2848 (Power of Attorney) or Form 8821 (Tax Information Authorization), the IRS assigns them a unique nine-digit CAF number and mails a confirmation letter.3Internal Revenue Service. The Centralized Authorization File (CAF) – Authorization Rules The number stays with the professional permanently. It follows the person, not the client or the tax matter, and IRS personnel use it to pull up every taxpayer who has authorized that professional and the exact scope of each authorization.
One quick clarification, because it comes up often: a CAF number is not a PTIN. A Preparer Tax Identification Number is required for anyone who prepares federal returns for compensation and must be renewed each year.4Internal Revenue Service. PTIN Requirements for Tax Return Preparers A CAF number only comes into play when a professional needs to interact with the IRS on a client’s behalf. Plenty of preparers have a PTIN and never need a CAF number.
Looking Up Your Own CAF Number as a Tax Professional
The Practitioner Priority Service line, 866-860-4259, is the dedicated route for retrieving a CAF number you can’t find.1Internal Revenue Service. What Is a CAF Number You’ll authenticate on the call, which includes providing your Short ID, an 8-to-10-character alphanumeric code assigned when your IRS account was first set up. If the Short ID has also slipped your memory, sign in to your e-Services Secure Object Repository and it will be there.5Internal Revenue Service. Practitioner Priority Service
The other lookup path is the Tax Pro Account. Once you link your CAF number to your account profile, you can see every active authorization on record: Powers of Attorney and Tax Information Authorizations, individual and business clients alike.6Internal Revenue Service. Tax Pro Account Linking is a one-time step under your account profile (“Link a CAF number”). After that the Tax Pro Account works as a live dashboard, and you can even withdraw from an authorization from within the interface rather than sending paper.
A note on order of operations: the online lookup only works after you’ve linked. If you’re locked out because you never linked and can’t remember the number, the phone line is the way in.
Checking Who Has Authorization on Your Account as a Taxpayer
If you’re the taxpayer, your IRS Online Account is where you review, electronically sign, and manage third-party authorizations.2Internal Revenue Service. Power of Attorney and Other Authorizations Sign in and the IRS displays your active authorizations. You don’t need to know any representative’s CAF number to do this; the system already has them mapped to your account.
This is the right place to confirm that a current representative’s authorization is active, and it’s the right place to check whether a former representative still has access. That second use case matters more than most people expect. If you changed accountants a couple of years back but never revoked the prior one, that person may still be authorized to receive your confidential tax information. Checking the Online Account every so often is the simplest way to catch a stale authorization before it becomes a problem.
What to Do If the Lookup Turns Up Someone Who Shouldn’t Be There
Finding an authorization you no longer want is the common reason taxpayers run this check in the first place. There are a few ways an authorization can end.
Filing a New Form Can Revoke an Old One
Filing a new Form 2848 automatically revokes all earlier Powers of Attorney on file for the same tax matters and periods, unless you check the retention box on Line 6 and attach copies of the authorizations you want to preserve.7Internal Revenue Service. Form 2848 (Rev. January 2021) Form 8821 goes further: a new Tax Information Authorization revokes all prior ones on file, not just those covering the same matters, unless you attach copies and check the retention box.8Internal Revenue Service. Instructions for Form 8821 (09/2021) And filing a new 2848 does not revoke an existing 8821, and vice versa; they’re tracked separately.9Internal Revenue Service. Instructions for Form 2848 (09/2021)
Revoking Directly Without Naming a New Representative
To revoke without appointing anyone new, write “REVOKE” across the top of the original authorization form, add your current signature and date under the annotation, and fax or mail it to the CAF unit.9Internal Revenue Service. Instructions for Form 2848 (09/2021) Don’t have the original? Send a written statement identifying the representative by name and address, listing the tax matters and periods, and signing and dating it. To revoke everything a representative has at once, write “revoke all years/periods” rather than listing them.
Representatives Can Withdraw From Their Side
A representative who wants out files a signed statement with the CAF unit including the taxpayer’s name, taxpayer identification number, address if known, and the matters and periods being withdrawn.9Internal Revenue Service. Instructions for Form 2848 (09/2021) Representatives who have linked their CAF number to a Tax Pro Account can withdraw in real time through the online interface and skip the paper process.6Internal Revenue Service. Tax Pro Account
Automatic Expiration Eventually
Even without action, authorizations don’t sit on the CAF forever. Standard authorizations are purged seven years from the taxpayer’s signature date. Estate tax authorizations for Form 706 stay on file for fifteen years. Qualifying student and law graduate authorizations expire after 130 days. All authorizations terminate on the taxpayer’s death once the IRS receives verification.10Internal Revenue Service. De-CAFinating Your Client Authorizations Seven years is a long time to leave old access in place. If an engagement has ended, revoking now is better than waiting for the purge, because a former representative with an active authorization can still call the IRS and receive your confidential information.
If Your CAF Number Lookup Shows a Problem
Occasionally a tax professional runs a lookup and finds the number has been flagged. The IRS screens incoming authorization forms for suspicious characteristics, and when a CAF employee flags a form as potentially fraudulent, processing stops and the case is escalated. Two status codes are relevant. “Pending” suspends all activity on the CAF number while the IRS investigates. “Cancelled” means the number has been confirmed as compromised, and the case goes to the IRS Incident Response Team.11Internal Revenue Service. Processing Third-Party Authorizations onto the Centralized Authorization File (CAF)
If you’re a tax professional and you suspect someone has used your CAF number without permission, report it to the IRS through the CAF unit or the Practitioner Priority Service line right away. If you’re a taxpayer and your Online Account shows an authorization to a name you don’t recognize, revoke it using the steps above and contact the IRS.