Guide
Federal Tax ID Number Guide
A Federal Tax ID is the same as an EIN. Both name the 9-digit IRS tax identification number for businesses. Apply free at irs.gov (SSN required) or through ein.so for $49 (non-residents).
A Federal Tax ID and an EIN are the same 9-digit number from the IRS. When people say Federal Tax ID for a business, they mean the Employer Identification Number (EIN). The format is XX-XXXXXXX, for example 12-3456789. US residents apply free at irs.gov using an SSN. Non-residents file Form SS-4 by fax with a passport number, and ein.so handles that for $49 Standard (4-7 business days) or $97 Express (2-3 business days).
A Federal Tax ID number identifies a business to the IRS the way a Social Security Number identifies an individual. The IRS issues the number once and it never changes for the life of the entity. Banks, payment processors, and the IRS all reference this single number. The terms Federal Tax ID, EIN, FEIN, and Federal Employer Identification Number all point to the same 9-digit identifier. This guide explains what the number is, who needs one, how US residents and non-residents each apply, and the annual filings that follow.
| Factor | Detail |
|---|---|
| Official name | Employer Identification Number (EIN) |
| Issuing agency | Internal Revenue Service (IRS) |
| Format | XX-XXXXXXX (9 digits) |
| Government cost | $0 |
| Online method | Instant (SSN required) |
| Fax method | 4-7 business days (no SSN needed) |
| ein.so Standard | $49, 4-7 business days |
| ein.so Express | $97, 2-3 business days |
Same Number
Is a Federal Tax ID the Same as an EIN?
Yes. A Federal Tax ID and an EIN are the same 9-digit IRS number. The IRS calls it an Employer Identification Number. Business owners, banks, and software call it a Federal Tax ID, a FEIN, or a Tax ID. All four terms name one identifier.
The number's official name is Employer Identification Number, but you do not need employees to get one. A single-member LLC with zero employees still uses an EIN. The word "employer" in the name is historical. The table below maps the common synonyms to the one underlying number.
| Term | Same Number? | Who Uses It |
|---|---|---|
| EIN | Yes | IRS forms, official documents |
| Federal Tax ID | Yes | Banks, vendors, contracts |
| FEIN | Yes | Payroll and state filings |
| Business Tax ID | Yes | Payment processors |
| Federal Employer ID | Yes | Tax preparation software |
See EIN vs Federal Tax ID and FEIN vs EIN for full explanations. A Federal Tax ID is not the same as a state tax ID, and it differs from an ITIN, which identifies individuals rather than businesses.
Who Needs One
Who Needs a Federal Tax ID Number?
Every US business entity needs a Federal Tax ID. All LLCs, corporations, and partnerships must hold an EIN to open a bank account, hire staff, and file federal returns. A foreign-owned single-member LLC needs one to file its required information returns each year.
The IRS requires a Federal Tax ID when a business does any of the following. Each trigger below maps to a real obligation, not a preference.
Opens a US Bank Account
Forms an LLC or Corporation
Hires Employees
Sells on US Platforms
If you run a US business and check any box above, you need a Federal Tax ID. Sole proprietors with no employees can use an SSN, but most still get an EIN to keep business and personal numbers separate.
How to Get
How Do You Get a Federal Tax ID?
You get a Federal Tax ID by filing IRS Form SS-4. The IRS offers four methods: online (instant, SSN required), fax (4-7 business days), phone (for international applicants), and mail (4-6 weeks). The IRS charges $0 for every method.
The right method depends on whether you have a Social Security Number. US residents with an SSN use the online tool for an instant number. Non-residents without an SSN cannot use the online tool, so they file by fax. The table below compares the four methods.
| Method | Speed | SSN Needed | Cost |
|---|---|---|---|
| Online | Instant | Yes | Free |
| Fax | 4-7 business days | No | Free / $49 |
| Phone (international) | Same call | No | Free |
| 4-6 weeks | No | Free |
The fax number for the IRS EIN unit is 855-215-1627. See how to get an EIN for the complete walkthrough and EIN processing time for current speed details. The IRS never charges a fee, so a free EIN is always available through the government directly.
Non-Residents
How Do Non-Residents Get a Federal Tax ID Without an SSN?
Non-residents get a Federal Tax ID by filing Form SS-4 by fax to 855-215-1627. You enter your passport number on Line 7b instead of an SSN. The IRS online tool requires an SSN, so the fax method is the path for non-residents. The IRS issues most correct filings in 4-7 business days.
No SSN and no ITIN are needed. Your passport number is sufficient identification on Line 7b. The most common rejection cause is a malformed international address, because the IRS silently rejects addresses that do not fit the SS-4 layout. ein.so reformats your address to an IRS-accepted style before filing.
Form Your US Entity
Gather Your Documents
Complete Form SS-4
Submit by Fax and Receive Your EIN
ein.so completes and files Form SS-4 for you for $49 Standard or $97 Express, then delivers your EIN by email. See how to get an EIN without an SSN and EIN for non-residents for full coverage.
Form SS-4
What Goes on Form SS-4 for a Federal Tax ID?
Form SS-4 is the single IRS form that requests a Federal Tax ID number. It collects the entity name, address, responsible party, reason for applying, and principal business activity. A foreign applicant enters a passport number on Line 7b in place of an SSN.
The form is one page. Most fields are simple, but Line 7b and the address fields cause the most rejections for non-residents. The field guide below shows what each key line needs.
| SS-4 Field | What to Enter |
|---|---|
| Line 1 (Legal name) | Your US entity name |
| Line 4 (Mailing address) | Your foreign address, reformatted for the IRS |
| Line 7a (Responsible party) | Your full name as shown on your passport |
| Line 7b (SSN/ITIN/EIN) | Your passport number (non-residents) |
| Line 8a (LLC?) | Yes, with the number of members |
| Line 10 (Reason for applying) | Started new business |
| Line 16 (Principal activity) | E.g., "software," "e-commerce," "consulting" |
A single typo or a mismatched name on Line 7a delays the EIN by weeks. ein.so checks each field against your passport and entity records before faxing. Read the full SS-4 form guide for line-by-line detail.
Federal vs State
Is a Federal Tax ID the Same as a State Tax ID?
No. A Federal Tax ID (EIN) comes from the IRS and applies across all 50 states. A state tax ID comes from a state revenue department and covers state sales tax or state payroll withholding. Many businesses hold both numbers at once.
The two identifiers serve different agencies. The federal number handles income tax, payroll reporting to the IRS, and banking. The state number handles state-level obligations that vary by state. You get the federal EIN first, then register for any state ID your activity requires.
| Factor | Federal Tax ID (EIN) | State Tax ID |
|---|---|---|
| Issued by | IRS | State revenue department |
| Scope | Nationwide | Single state |
| Used for | Federal tax, banking, payroll | State sales tax, state payroll |
| Cost | $0 | Varies by state |
| Required for | All LLCs, corporations | Activity that triggers state tax |
Confirm your state registration duties with a CPA, because state thresholds for sales tax and payroll differ widely. The federal EIN is the universal starting point.
Annual Filings
What Filings Does a Federal Tax ID Trigger?
A foreign-owned single-member US LLC must file Form 5472 with a pro-forma Form 1120 each year. The IRS penalty for not filing is $25,000. The Federal Tax ID is required before any of these filings, because the EIN identifies the entity on every return.
The EIN itself is just an identifier. The filings below are the obligations it unlocks. ein.so files the EIN and does not provide tax advice, so confirm specifics with a CPA.
Form 5472 + Pro-Forma 1120
BOI Report to FinCEN
Payroll Returns
Annual Income Tax Return
ein.so handles the EIN application only and does not give tax advice. Work with a US CPA who understands non-resident filing. See EIN for non-residents and the Form 5472 guide for context.
ITIN Difference
How Does a Federal Tax ID Differ From an ITIN?
A Federal Tax ID (EIN) identifies a business, while an ITIN identifies an individual. The IRS issues an EIN to companies and an ITIN to people who cannot get an SSN but must file a personal US tax return. The two numbers are not interchangeable.
You do not need an ITIN to get an EIN. A passport number on Line 7b is enough for the SS-4 filing. Some non-residents later need an ITIN for personal tax filings or treaty claims, which is a separate process. ein.so offers an ITIN service for $197 Standard or $297 Express, distinct from the $49 EIN service.
| Factor | Federal Tax ID (EIN) | ITIN |
|---|---|---|
| Identifies | A business entity | An individual person |
| Format | XX-XXXXXXX | 9XX-XX-XXXX |
| Needed for EIN? | No, it is the EIN | No |
| ein.so price | $49 / $97 | $197 / $297 |
See the EIN without SSN guide to confirm that no ITIN is required for your EIN. Get the EIN first, then add an ITIN only if a CPA confirms you need one.
Next Steps
After You Get Your Federal Tax ID
- Open a US bank account — Mercury, Relay, and Wise accept non-resident LLC owners with an EIN and passport
- File your BOI report — required for most LLCs, filed at fincen.gov/boi
- File Form 5472 — annually for foreign-owned LLCs, with a $25,000 penalty for non-filing
- Confirm state registration — a state tax ID is separate from your federal EIN
- Verify the basics — review how to get an EIN, EIN without an SSN, and EIN processing time
Related reading: What is an EIN | EIN cost | EIN by fax | SS-4 form guide | EIN for non-residents
Frequently Asked Questions
Is a Federal Tax ID the same as an EIN?
Yes. A Federal Tax ID and an EIN are the same 9-digit number issued by the IRS. The terms are fully interchangeable, along with FEIN and Federal Employer Identification Number. The format is XX-XXXXXXX, for example 12-3456789. Every US LLC, corporation, and partnership uses this single number for federal tax purposes.
How do I get a Federal Tax ID number?
You get a Federal Tax ID by filing IRS Form SS-4. US residents apply online for an instant number using an SSN. Non-residents file by fax to 855-215-1627 using a passport number on Line 7b. The IRS charges $0. ein.so files the SS-4 for you for $49 Standard or $97 Express.
Is a Federal Tax ID free?
Yes. The IRS charges $0 for a Federal Tax ID number. No government fee exists for an EIN. ein.so charges $49 Standard (4-7 business days) or $97 Express (2-3 business days) for non-resident filing assistance, preparing and faxing Form SS-4 and delivering the EIN by email. The IRS fee remains $0.
Do I need a Federal Tax ID for my business?
If you operate a US business entity, yes. Every US LLC, corporation, and partnership needs a Federal Tax ID (EIN) to open a bank account, hire employees, and file federal tax returns. A foreign-owned single-member LLC needs an EIN to file Form 5472 and a pro-forma Form 1120 each year.
Can a non-US resident get a Federal Tax ID without an SSN?
Yes. A non-US resident gets a Federal Tax ID without an SSN or ITIN by filing Form SS-4 by fax. You enter your passport number on Line 7b instead of an SSN. The IRS online tool requires an SSN, so non-residents use the fax method that ein.so handles for $49.
What is the format of a Federal Tax ID number?
A Federal Tax ID uses the format XX-XXXXXXX: nine digits with a hyphen after the second digit. An example is 12-3456789. This is identical to an EIN. A Social Security Number uses XXX-XX-XXXX instead. The two-digit prefix once signaled the issuing IRS campus but no longer reflects location.
How long does it take to get a Federal Tax ID?
Online applications with an SSN return a Federal Tax ID instantly. Fax filings take 4-7 business days when the SS-4 is error-free. Mail takes 4-6 weeks. Through ein.so, Standard processing takes 4-7 business days ($49) and Express takes 2-3 business days ($97). See the EIN processing time guide for details.
Is a Federal Tax ID the same as a state tax ID?
No. A Federal Tax ID (EIN) comes from the IRS and applies nationwide. A state tax ID comes from a state revenue department for state-level sales tax or payroll. Many businesses hold both: one federal EIN and one or more state tax registrations. The two numbers serve different agencies and purposes.
Can I look up a Federal Tax ID number?
You find your own Federal Tax ID on your IRS CP 575 assignment letter, prior tax returns, or bank records. The IRS does not run a public EIN lookup tool. To recover a lost EIN, call the IRS Business and Specialty Tax Line. ein.so emails your EIN assignment letter after filing.
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