What else is a federal tax ID number called?
Six names cover the same number: federal tax ID number, EIN, FEIN, federal tax identification number, business tax ID number, and tax ID number. Each names one 9-digit IRS assignment.
| Name | Short form | Where you meet it | Same number |
|---|---|---|---|
| Federal Tax ID Number | Federal Tax ID | Bank account applications, merchant accounts, state licence forms | Yes |
| Employer Identification Number | EIN | The IRS name. Form SS-4, the CP-575 letter, Form W-9 line 6 | Yes |
| Federal Employer Identification Number | FEIN | State payroll registrations and unemployment insurance forms | Yes |
| Federal Tax Identification Number | Federal TIN | Vendor onboarding portals and supplier records | Yes |
| Business Tax ID Number | Business Tax ID | Payment processors, marketplaces, invoicing software | Yes |
| Tax ID Number for a business | Tax ID | Everyday speech, accountants, insurance applications | Yes |
Source: IRS naming on Form SS-4 and the CP-575, verified July 2026.
The naming split has a cause. The IRS built the number for employers in the first place, so its legal name is Employer Identification Number. Everyone outside the IRS then needed a phrase for it that did not imply employees, because a business with 0 employees still holds one. Federal tax ID number became that phrase, and FEIN became the state-agency version of it.
The practical rule is short. Read the field, write the 9 digits from your CP-575, and ignore the label. No form in the list above asks for a different number, and none of them accepts a different one.
What does a federal tax ID number look like?
Nine digits in the pattern XX-XXXXXXX: 2 digits, a hyphen, then 7 digits. A Social Security Number uses the same 9 digits split 3-2-4 instead, which is how the two are told apart on sight.
| Number | Digits | Pattern | Example shape |
|---|---|---|---|
| Federal tax ID number (EIN) | 9 | 2 then 7 | 12-3456789 |
| Social Security Number | 9 | 3 then 2 then 4 | 123-45-6789 |
| ITIN | 9 | 3 then 2 then 4, starting with 9 | 9XX-XX-XXXX |
| State tax ID | Varies by state | Set by the state | Not federal |
Source: IRS publications on taxpayer identification numbers, verified July 2026.
The 2-digit prefix records which IRS campus assigned the number. It is a processing marker, not a geography marker: a business in one state holds a prefix issued by a campus in another, and that mismatch invalidates nothing. Reading a state out of the prefix produces a wrong answer every time.
The hyphen is presentation only. Systems that store the number strip it, so 12-3456789 and 123456789 are the same record. What breaks a match is a digit, not punctuation. An EIN uses only the 10 digits 0 through 9 and never a letter, so a character keyed as the letter O is a 0 and any of the 26 letters appearing in the field marks the value as a misread rather than a valid EIN.
A full anatomy of the format, prefix by prefix, sits on the ein number example page.
What is not a federal tax ID number?
Five numbers get mistaken for it: a state tax ID, a Social Security Number, an ITIN, a DUNS number, and a state sales tax permit number. None is issued by the IRS on Form SS-4, and none substitutes.
| Number | Issued by | What it identifies | Replaces the EIN |
|---|---|---|---|
| State tax ID | A state revenue department | A business for state withholding or sales tax | No |
| Social Security Number | The Social Security Administration | An individual | No |
| ITIN | The IRS, on Form W-7 | An individual with a US filing duty and no SSN | No |
| DUNS number | A private commercial data company | A business for credit reporting | No |
| Sales tax permit number | A state or local authority | A seller collecting sales tax | No |
Source: IRS and state revenue department publications, verified July 2026.
The state number is the one that costs people the most time. A business operating in 3 states holds 1 federal number and up to 3 separate state numbers, each issued by a different agency on a different form. A payroll registration that asks for the FEIN wants the federal 9 digits, and the field beside it asking for a state account number wants a different number entirely.
The identity numbers separate on a cleaner rule. An EIN identifies an entity, and an SSN or an ITIN identifies a person. Read the differences in full on the ein vs ssn page and the ein vs itin page, or see all 5 identification numbers ranked on the ein vs tin page.
Which entities are assigned a federal tax ID number?
Corporations, partnerships, multi-member LLCs, trusts, estates, and nonprofits each hold one. A sole proprietor with 0 employees files under a Social Security Number until a bank or a payer requires the 9-digit number.
| Entity | Federal number required | Return it prints on |
|---|---|---|
| C corporation | Yes | Form 1120, page 1 |
| S corporation | Yes | Form 1120-S, page 1 |
| Partnership | Yes | Form 1065, page 1 |
| Multi-member LLC | Yes | Form 1065 or Form 1120 |
| Single-member LLC with employees | Yes | Form 941, page 1 |
| Single-member LLC, no employees | On request by a bank or payer | Schedule C with Form 1040 |
| Sole proprietor with employees | Yes | Form 941, page 1 |
| Trust | Yes | Form 1041, page 1 |
| Estate | Yes | Form 1041, page 1 |
| Nonprofit | Yes | Form 990, page 1 |
Source: IRS return instructions, verified July 2026.
Nine of the 10 rows above answer yes outright. The single exception, a single-member LLC with no employees, is the row that produces the most questions, because the IRS treats that entity as disregarded for income tax while banks and payment processors still require a number that is not the owner’s SSN. Work through the decision entity by entity on the do i need an ein page, or read the LLC chapter on the ein for llc page.
Where does a federal tax ID number print?
On the CP-575 letter first, then page 1 of a business return, box b of a W-2, line 6 of a W-9, and the bank account application. Checking each of those 5 sources costs $0.
| Document | Field name printed there | Time to check |
|---|---|---|
| CP-575 confirmation letter | Employer Identification Number | 1 minute |
| Form 1120 or Form 1065 | Employer identification number | 2 minutes |
| Form W-2, box b | Employer identification number | 2 minutes |
| Form W-9, line 6 | Employer identification number | 2 minutes |
| Bank account application | Federal Tax ID Number | 5 minutes |
| Merchant or marketplace profile | Business Tax ID | 5 minutes |
| State payroll registration | FEIN | 5 minutes |
Source: IRS forms and standard bank onboarding forms, verified July 2026.
Four different field names appear across those 7 documents, and all 7 carry the identical 9 digits. That is the practical proof of the synonym: the number is stable and only the vocabulary moves. The document a bank treats as primary is the CP-575, because it is the one that records the pairing of the number with the exact legal name the IRS holds. Read what that letter contains on the CP-575 page.
How do you get a federal tax ID number?
File Form SS-4. Four IRS routes exist: online in 15 minutes, phone on 267-941-1099 for international applicants, fax in 4 business days, and mail in 4 weeks. The IRS charges $0 on all 4.
| Route | Time | Needs an SSN or ITIN | Cost |
|---|---|---|---|
| IRS online tool | 15 minutes | Yes | $0 |
| IRS phone, 267-941-1099 | During the call | No | $0 |
| Fax, 855-641-6935 or 855-215-1627 | 4 business days | No | $0 |
| 4 weeks | No | $0 | |
| ein-number.com | 7 business days or 100% automatic refund | No | $99 |
Source: IRS Form SS-4 instructions, verified July 2026. Business days are Monday to Friday, excluding US federal holidays.
One rule separates the 4 IRS routes. The online tool asks the responsible party for an SSN, an ITIN, or an existing EIN, and the other 3 routes ask for none of those. That single requirement decides which route applies to you before any question of speed enters the picture.
Fax beats mail by a factor of 5 on the same form: 4 business days against 20. The condition is a return fax number on the application, because the IRS replies to the number printed there and to nothing else. Compare all 5 routes side by side on the how long does it take to get an ein page, and read the line-by-line application walkthrough on the how to apply for an ein page.
A rejected application returns a reference number rather than an EIN, and reference 101 accounts for the largest share of them: a name conflict against an existing IRS record. Read the fix for each code on the ein reference number 101 page.
How much does a federal tax ID number cost?
The IRS charges $0 on all 4 of its routes, and the number never renews, so year 2 costs $0. Any amount you pay is a filing service fee, never an IRS fee.
| Filed by | Price | Written deadline | Year 2+ |
|---|---|---|---|
| Yourself, direct to the IRS | $0 | None | $0 |
| ein-number.com | $99 | 7 business days or 100% automatic refund | $0 |
| Northwest | $200 | None | $0 |
| ZenBusiness | $99 | None | $0 |
| Rocket Lawyer | $59.99 | None | $0 |
Competitor prices verified July 2026. Northwest reflects the no-SSN rate. The year 2 column reads $0 on every row because an EIN never renews.
The $0 IRS fee is the fact to hold on to. What a filing service sells is preparation and a delivery commitment, not access to the number. Our $99 covers Form SS-4 prepared and checked against your formation document, filing within 1 business day of your completed details, 4 tracked stages, and a delivery date in writing. Two of the 3 services above match or beat that price and none of the 3 publishes a written deadline. The full cost breakdown sits on the EIN cost page.
You can get your EIN number in 7 business days or file the same Form SS-4 yourself for nothing. Both are honest answers, and which one fits depends on whether a date in writing is worth $99 to you.
Can you get a federal tax ID number without an SSN?
Yes. Form SS-4 line 7b accepts the entry Foreign, so the IRS assigns the number to a responsible party with no SSN and no ITIN. The route is fax, 4 business days, at $0.
Have an SSN? irs.gov is free, and the online tool issues the number in 15 minutes.
No SSN? The fax route works, 4 business days, also $0. Or we file it for $99 with a written date.
The mechanics are narrower than the reputation suggests. Line 7b of Form SS-4 takes the word Foreign in place of an identification number. Line 4a and line 4b accept a mailing address outside the United States. No identity document accompanies the form, so there is no passport upload at any step, and no visit to the United States is part of the process.
| Item | Requirement |
|---|---|
| SSN for the responsible party | Not required, line 7b accepts Foreign |
| ITIN for the responsible party | Not required |
| Passport or identity document | Not filed with Form SS-4 |
| US mailing address | Not required, lines 4a and 4b accept a foreign address |
| US fax line for entities in a US state | 855-641-6935 |
| IRS fax line for international applicants | 855-215-1627 |
| IRS international phone line | 267-941-1099 |
| IRS fee on the no-SSN route | $0 |
Source: IRS Form SS-4 and its instructions, verified July 2026.
The complete no-SSN reference, including what to write on each line, sits on the EIN without SSN page.
What do you do when the federal tax ID number is lost?
Check the CP-575, a filed return, a W-2, a W-9, and the bank file first. When no record survives, the IRS reissues the number as a 147C letter to an authorized person, at $0.
The IRS issues 1 CP-575 per number and never reprints it. That single fact explains why the recovery list runs to 5 document checks before any IRS contact: each document is a surviving copy of the same 9 digits. Four of those 5 checks finish inside 5 minutes.
An authorized person means an owner, a partner, a corporate officer, or a person holding a filed power of attorney. International callers reach the IRS on 267-941-1099. Work through the recovery order on the lost EIN number page, read the request script on the 147C letter page, or start from the method list on the EIN number lookup page.
When does a business need a new federal tax ID number?
When the legal entity changes, not when its details change. A sole proprietorship that incorporates needs a new number. An address change and a name change keep the same 9 digits and file Form 8822-B.
| Change | New number | What you file |
|---|---|---|
| Business address changes | No | Form 8822-B |
| Legal name changes | No | Form 8822-B or the return |
| Responsible party changes | No | Form 8822-B within 60 days |
| Sole proprietorship incorporates | Yes | Form SS-4 |
| Single-member LLC adds a second member | Yes | Form SS-4 |
| Partnership incorporates | Yes | Form SS-4 |
| Corporation converts to an LLC | Yes | Form SS-4 |
| Owner sells the business | Yes, for the buyer | Form SS-4 |
Source: IRS guidance on entity changes and Form 8822-B, verified July 2026.
Five of the 8 rows require a new application and 3 do not. The dividing line is whether a different legal entity now exists. The number belongs to the entity, so it survives every change that leaves the entity intact and ends with every change that replaces it. Read the full matrix on the when do you need a new EIN page, and the line-by-line change form on the Form 8822-B page.