A centralized authorization file (CAF) number from the Internal Revenue Service is a must-have for tax professionals who need access to client information to complete tasks and keep operations running efficiently.
What you’ll learn
What you’ll learn
Updated: April 16, 2025
Key takeaways
- A centralized authorization file (CAF) number is a nine-digit identifier issued by the Internal Revenue Service (IRS) to tax professionals that communicate with the agency on behalf of clients
- CAF numbers are used by the IRS to track and manage the authorizations taxpayers grant to tax professionals; they are representation identifiers
- Without a CAF number, providing clients with a robust service offering is next to impossible
In this guide, we’ll cover what a CAF number is, why it matters, and how to apply for one.
What is an IRS CAF number?
A centralized authorization file (CAF) number is a nine-digit identifier assigned by the Internal Revenue Service (IRS) to tax professionals. It is used to track the authorizations that taxpayers grant to practitioners — including access to confidential tax information and granting representation rights.
Unlike a preparer tax identification number (PTIN), a CAF number does not authorize a tax professional to provide paid tax preparation services. Rather, it is a way for the IRS to track and manage the power of attorney and tax information authorization forms (Form 2848 and Form 8821) filed by tax professionals.
Good to know
The centralized authorization file is an IRS database. It includes details of the legal authorizations that have been filed by tax professionals. It is used by IRS agents to quickly verify whether a professional has the necessary authority to access specific taxpayer data. All tax professionals that have been assigned a CAF number are in the database.
Now that we better understand the purpose of a CAF form, let’s find out more about why most accounting professionals will want to be familiar with it.
Why is having a CAF number important for tax professionals?
Having a CAF number is essential for tax professionals who communicate with the IRS on behalf of clients. Typically, this includes CPAs, enrolled agents, bankruptcy lawyers, and other authorized representatives who need to have correspondence with the IRS on behalf of their clients.
In a nutshell, a CAF number streamlines interactions with the IRS, enabling agents to quickly verify information access rights and expedite the resolution of tax matters. Without one, you cannot legally represent clients or access their confidential tax records. The takeaway is that this significantly affects your ability to address IRS issues, build trust with your clients, and could even prevent your practice from putting its best foot forward.
Next, let’s cover how you can go about getting one for your organization.
How can you apply for a CAF number from the IRS?
Obtaining a CAF number is straightforward, but it requires some attention to detail. You cannot apply for a CAF number directly. Rather, the IRS will assign you a CAF number when you first submit Form 2848 or Form 8821. To ensure the process goes smoothly, follow these steps:
- Complete Form 2848 or Form 8821, taking care to accurately disclose your personal information and your client’s details. Enter “none” in the space asking for a CAF number.
- Submit the form to the appropriate IRS office, either by mail or fax, per the Instructions for Form 2848 or the Instructions for Form 8821.
- Wait for confirmation from the IRS. You will receive your CAF number via mail, but it could take up to six weeks.
Common misconceptions about CAF numbers
As mentioned above, a CAF number is a tool used by the IRS to manage and track the power of attorney and tax information authorization forms filed by tax professionals. Its purpose is clear, though there are some common misconceptions we should touch on.
- A CAF number is the same as a PTIN. Many tax professionals mistakenly believe a PTIN doubles as a CAF number, but this is not true. A PTIN authorizes you to provide paid tax preparation services, while a CAF number allows you to represent clients and access confidential information.
- You can only have one CAF number. Most tax professionals operate with a single CAF number, but others prefer to hold more than one. Multiple CAF numbers are permitted to differentiate between multiple office addresses or related entities.
- CAF numbers expire. CAF numbers do not expire, but they can be deemed inactive if not used for an extended period. Regular use ensures active status.
Why a CAF number is key to supporting your clients’ tax needs
If you plan to represent clients before the IRS, obtaining a CAF number should be on your to-do list. Having one is essential for enhancing your professional capabilities, cultivating trust with clientele, and ensuring compliance with IRS regulations. If you do not already have a CAF number, it makes good business sense to get one so you’re ready for the future needs of your client base. Best of luck as you move your firm forward!
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Thomas is an accomplished financial professional, with over 20 years of experience in investments, corporate finance, and accounting. His investment experience includes oversight of a $4 billion portfolio for an insurance group. Varied finance and accounting work includes the preparation of financial statements and budgets, the development of multiyear financial forecasts, credit analyses, and the evaluation of capital budgeting proposals.