An FID number is a nine digit code the IRS assigns to a business for tax filing, payroll reporting, and banking purposes. It stands for Federal Identification Number, and in practice it means the same thing as an Employer Identification Number (EIN) and a Federal Employer Identification Number (FEIN). Most people search for “FID number” when they’re really looking for their EIN, so if a form or bank asks for one, your EIN is the number they want.
Businesses often use the terms FID number, EIN, and FEIN (Federal Employer Identification Number) interchangeably.
What Does an FID Number Look Like?
An FID number contains nine digits formatted like this:
XX-XXXXXXX
Example: 12-3456789
The first two digits historically represented the IRS processing center where the number was issued, although modern assignment is now largely centralized.
Why Is an FID Number Important?
An FID number allows the IRS and other government agencies to track business tax activity.
Businesses typically need an FID number for:
• filing federal tax returns
• reporting payroll taxes
• opening business bank accounts
• applying for business licenses and permits
• hiring employees
• issuing W-2 and 1099 forms
• establishing retirement plans
• applying for business credit
Who Needs an FID Number?
Most organizations operating in the United States require an FID number, including:
• corporations
• partnerships
• limited liability companies (LLCs)
• nonprofit organizations
• trusts and estates
Sole proprietors may also need an FID number if they hire employees, file employment taxes, or establish retirement plans.
FID Number vs. State Tax ID
An FID number and a state tax ID are not the same thing. Your FID number, meaning your federal EIN, is issued once by the IRS and used on federal filings. Most states also require a separate state tax ID number for state income tax withholding, unemployment insurance, or sales tax, and that number comes from your state’s department of revenue, not the IRS. A business typically needs both if it has employees.
How to Apply for an FID Number?
Businesses can apply for an FID number directly through the IRS. The process is free.
Online application
The online system is only open certain hours. As of 2026, the IRS EIN Assistant runs Monday through Friday from 6 a.m. to 1 a.m. Eastern time, Saturday from 6 a.m. to 9 p.m., and Sunday from 6 p.m. to midnight, according to the IRS’s own EIN application page. You’re also limited to one EIN per responsible party per day, so if you’re forming multiple entities, plan to apply on separate days.
Fax application
Submitting Form SS-4 by fax usually results in a response within a few business days.
Mail application
Mail applications may take several weeks to process.
How to Find an Existing FID Number?
If a business needs to locate its FID number, it can usually be found on:
• previous tax returns
• IRS confirmation letters
• payroll tax filings
• business bank records
• W-2 or 1099 forms
If the number cannot be located, the IRS Business and Specialty Tax Line can assist.
What Is the Difference Between an FID Number and a Social Security Number?
FID number
• identifies a business entity
• used for payroll and tax reporting
• issued by the IRS
Social Security Number (SSN)
• identifies an individual taxpayer
• used for personal tax reporting
• issued by the Social Security Administration
Key Takeaway
An FID number is a core identifier for businesses operating in the United States. It enables organizations to file taxes, hire employees, open financial accounts, and remain compliant with federal regulations. As organizations expand their workforce and HR operations, many also adopt modern people management platforms like Engagedly. You can request a demo to see how performance management, employee engagement, and development tools support growing teams.
Frequently Asked Questions About FID Numbers
Is an FID number the same as an EIN?
Yes. FID number and EIN refer to the same nine digit identifier issued by the IRS. Some states and older forms use “FID” as a leftover term from before “EIN” became standard, but they point to the same number.
Is a FID number the same as a tax ID number?
It’s one type of tax ID number. The IRS calls the broader category a Taxpayer Identification Number, or TIN, and an EIN or FID number is the version issued to businesses rather than individuals.
How long does it take to get an FID number?
Applying online through the IRS EIN Assistant issues the number immediately once the application is validated. Fax applications using Form SS4 usually take about four business days, and mail applications can take four weeks or longer, according to the
IRS Taxpayer Advocate Service.
Can I apply for an FID number if I’m not a US resident?
Only if your principal business is located in the United States or a US territory. If it isn’t, you can’t use the online system, and you’ll need to apply by fax or mail instead.
Is there a cost to get an FID number?
No. The IRS issues EINs at no charge. If a website charges a fee to “get your EIN for you,” you’re paying for a filing service, not the number itself.
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