Sep 12 2023 /

Understanding the CAF number: your complete guide

Understanding the CAF number

Interacting with the IRS on behalf of clients as a tax professional or an accountant requires meticulous authorization and adherence to proper procedures. A pivotal tool in this intricate landscape is the CAF number.

Within this comprehensive guide, we will delve deep into the realm of the CAF number, clarifying its importance and unveiling its role in dealings with the IRS. We’ll then take you step by step through the process of acquiring your very own CAF number and share invaluable insights from experts on securing and optimizing the use of this identifier.

So what exactly is a CAF Number?

CAF stands for Centralized Authorization File. It is a unique 9-digit number that the IRS gives to representatives the first time they submit a power of attorney or request access to tax information.

The CAF system is a database that keeps track of tax and accounting professionals who have the authority to act for other people. Having your unique CAF number eliminates the need for the IRS to repeatedly request authorization documents. Whenever you need to call the IRS on a client’s behalf or access their transcripts online, your CAF number serves as a shortcut for the IRS to instantly confirm your approved status by checking your file in the system.

In short, a CAF number is your key to streamlined access by letting the IRS instantly verify your authorizations are in order. It’s a time and paperwork saver!

How to Get a CAF Number

Obtaining your initial CAF number from the IRS could take between two and four weeks. To ensure you get your number in a timely manner, follow these steps:

1. Complete Form 2848 or 8821

Complete either IRS Form 2848 to represent your client before the IRS or Form 8821 to inspect their confidential tax return information. 

2. Input your information

On the form, include your personal or business information as an authorized representative. For the CAF number, input “NONE” since this is your first time applying.

3. Get taxpayer authorization

Have the taxpayer fill out and sign the form, ensuring all fields are completed accurately.

4. Submit the form

Send the completed form via mail or fax to the appropriate IRS office.

5. Use your new CAF number

Once received, use your assigned CAF number on any future requests. This unique 9-digit ID number is now associated with your authorization file.

If you have lost your CAF number and need assistance, call the Practitioner Priority Service at 866-860-4259.

Why a CAF Number Matters

Acquiring that first CAF number provides a gateway to more streamlined interactions with the IRS. Your personal CAF number lets you swiftly access client transcripts and tax documents via e-Services, all without the need to keep resubmitting forms. 

Furthermore, the IRS helpfully leverages the CAF number to directly dispatch client notifications, keeping you informed of significant activities. More than just an ID, a CAF number is essential for time savings and streamlining workflows. 

Using the CAF Number

Getting your CAF number is just the starting point—you’ll want to use it properly on an ongoing basis to reap the full benefits. Here’s how to maximize that unique ID after getting it:

  • Use CAF number consistently: utilize it for all future authorization forms and information requests to ensure efficient interactions
  • Keep it secure: treat your CAF number as sensitive information and do not share it freely
  • Verify annually: check that all clients with authorizations on file are still active and withdraw those that are inactive or no longer valid
  • Watch for suspicious activity: monitor use of your CAF number and report any potential misuse to the IRS immediately
  • Utilize online tools: take advantage of e-Services’ ability to seamlessly submit documents and access transcripts using your CAF number
  • Treat it as sensitive information: have it stored in a safe yet readily accessible place and do not share it freely. The IRS offers recommendations for securing taxpayer data

CAF Unit and Processing

When submitting authorization forms to obtain your CAF number, it is important to know where to send your paperwork based on location. The IRS has dedicated CAF Units that handle processing based on geographic regions: Ogden Accounts Management Campus (OAMC), Memphis (MAMC) and Philadelphia (PAMC). 

As a general rule, states west of the Mississippi should submit to OAMC, while states east of the Mississippi should submit to MAMC.


  • International taxpayers go to PAMC
  • Arkansas and Louisiana submit to MAMC
  • Wisconsin submits to Ogden

For the most up-to-date contact information and details on the CAF Units, please visit the IRS website

Addressing Rejections and Resources

When submitting forms to obtain your CAF number, it is crucial to avoid mistakes that could lead to rejection and delays. Here are some tips:

  • Provide complete and accurate taxpayer information, such as SSNs, addresses, titles, names, etc.
  • Check that all signatures and dates are present
  • Only request access needed and avoid vague wording like “all years/periods” 
  • Double check form accuracy to avoid simple but preventable mistakes

If a CAF request is rejected, promptly address any deficiencies and resubmit the form. 

Beyond avoiding rejections, taking advantage of IRS resources can support the CAF application process:

  • Publication 947, that covers practice before the IRS with authorization details
  • Form 2848 for power of attorney authorizations
  • Form 8821 for tax information authorizations

Taking advantage of IRS guidance, adhering to form instructions, and paying attention to detail will help ensure effective processing of your CAF number request.

Wrapping up

If you are a tax professional who needs fast and easy access to IRS client data, you will need to apply for a Centralized Authorization File (CAF) number. It serves as your unique identifier that enables the IRS to instantly verify your credentials.

By following the proper steps to get your initial CAF number assigned and then leveraging it appropriately for all future interactions, you can optimize your workflows. Keeping your number secure will facilitate effective processing.

With the help of this comprehensive overview, you now understand the significance of a CAF number, how to acquire one, and the best practices for properly using it as a tax and accounting professional. Put this guide’s insights into practice to maximize its value and improve your IRS interactions.

Mari Sam

Mari Sam is a content writer at TaxDome who is passionate about crafting compelling copy. Her job is to ensure that TaxDome clients fully utilize the platform's latest features and enhancements. Through clear communication of updates, changes, and new capabilities, Mari produces engaging content that enables clients to make the most out of the platform.

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