Overview

An EIN is not different from a TIN—it’s one type of TIN used for businesses. If you operate as an individual, your TIN is typically an SSN. If you operate through a business entity or want privacy on W‑9s, you’ll generally use an EIN. For official definitions and subtypes in one place, see IRS: Taxpayer Identification Numbers (TIN).

This guide gives you a quick decision path, step‑by‑step application instructions (including for international founders without SSNs/ITINs), and practical compliance tips so you set up correctly and avoid penalties.

TIN vs EIN in plain terms

A TIN (Taxpayer Identification Number) is an umbrella term the IRS uses for the numbers that identify taxpayers. Subtypes include SSN (individuals), EIN (businesses), ITIN (non‑U.S. individuals without SSNs), ATIN (adoptive children), and PTIN (paid tax preparers)—and yes, an EIN is a type of TIN.

In day‑to‑day terms: when you’re acting as a person, you usually use an SSN. When you’re acting as a business, you use an EIN. Some exceptions exist (for example, a sole proprietor can use an SSN but may choose an EIN for privacy on W‑9s). When in doubt, choose the identifier that matches who’s recognized as the taxpayer on the return or information form you’re filing.

Who issues which numbers and what they’re used for

SSNs come from the Social Security Administration, while the IRS issues EINs, ITINs, ATINs, and PTINs for tax administration. You’ll use these identifiers to file returns, complete withholding certificates, run payroll, and provide vendor/contractor information.

A typical flow looks like this: vendors give payers a completed Form W‑9 with their correct TIN. Payers report income on 1099s, and employers use EINs for payroll tax filings. Keeping the right TIN on the right form reduces mismatches and penalties; for details on what payers need from W‑9s, see IRS: Instructions for the Requester of Form W‑9.

Do you need an EIN? A decision framework by entity and scenario

If you formed an entity (LLC, corporation, partnership, nonprofit) you almost certainly need an EIN. If you’re a sole proprietor with no employees, you can often use your SSN, but many still obtain an EIN for banking, payments, or W‑9 privacy.

Think about your immediate needs: hiring employees, opening a business bank account, onboarding with processors (e.g., Stripe), sponsoring retirement plans, or filing excise/payroll taxes. If any apply—or you want to avoid sharing your SSN—get an EIN now. It’s free and quick to obtain directly from the IRS.

Sole proprietors and single‑member LLCs (disregarded entities)

Sole proprietors without employees can generally use an SSN, but an EIN is required if you hire employees or file excise or certain employment tax returns. Single‑member LLCs that are “disregarded” for tax purposes can often report with the owner’s SSN. They commonly obtain an EIN for banking, payroll setups, processor accounts, and to avoid placing SSNs on W‑9s.

If your SMLLC elects corporate tax treatment (Form 8832/2553) or you start payroll, you’ll need an EIN. As a practical matter, many vendors, marketplaces, and banks will ask for an EIN to onboard your company as a distinct legal entity.

Partnerships, multi‑member LLCs, corporations, and nonprofits

Partnerships, multi‑member LLCs, C‑corps, S‑corps, and most nonprofits require an EIN because the entity—not an individual—files returns. An S‑corp election doesn’t itself change your EIN. It just changes how your existing entity is taxed.

If you reorganize or convert entities, you may need a new EIN depending on the transaction. The IRS outlines specific change events that trigger new EINs in its guidance.

Trusts and estates

Estates and many trusts need their own EINs because they file separate returns. For example, an irrevocable trust or an estate administering a decedent’s assets must obtain a distinct EIN. You use it to report income and pay any taxes due.

Some grantor trusts may use the grantor’s SSN, but professional practice often favors a separate EIN for clarity with banks, payers, and year‑end reporting. Check your trust type and filing obligations before you open accounts or receive income.

Foreign owners and entities

Foreign‑owned U.S. entities typically need an EIN, even if no U.S. employees exist. You need it to file returns, open bank/processor accounts, and meet compliance rules. You can obtain an EIN without an SSN or ITIN by submitting Form SS‑4 and using the international application path.

The responsible party must be listed on SS‑4 (even if they don’t have a U.S. TIN). You’ll find the mechanics and line‑by‑line tips in the International Founders section below and the official instructions.

Costs, timing, and how to apply for an EIN

An EIN is free when you apply directly with the IRS, and online issuance can be immediate for eligible applicants (IRS). You can apply online, by fax or mail, or by phone if you’re an international applicant. Timing varies by channel. Use the official portal at IRS: Apply for an Employer Identification Number (EIN) Online.

Choose the channel that fits your situation. Online is fastest for U.S. applicants; fax is a solid backup if you’re ineligible for online; mail works but is slow; and international applicants can apply by phone after completing SS‑4. Reference the current instructions for eligibility and processing notes.

Online application

If your principal business is in the U.S. or U.S. Territories and you have a valid taxpayer responsible party, the online application can issue an EIN immediately. The session times out if you pause too long, so gather your SS‑4 details first and plan to apply during posted service hours.

Avoid third‑party websites that charge fees—EINs are free from the IRS. Confirm eligibility, prepare your responsible party information, and apply through the official portal linked above.

Fax and mail

Use fax or mail if you’re ineligible for online or prefer a paper trail. Faxed SS‑4s commonly turn around in about a week when a return fax number is provided; mailed applications can take several weeks depending on IRS volume.

To avoid rejections, make sure your entity type on line 9 matches your formation documents and your “reason for applying” on line 10 is clear (e.g., “Started a new business” or “Hired employees”). The line‑by‑line instructions help you avoid common pitfalls.

International phone option

International applicants with no U.S. legal residence can apply by phone after completing SS‑4. Be ready to provide the responsible party’s name, a non‑U.S. address that accepts mail, and precise answers for line 9 (entity type), line 10 (reason), and line 11 (start/acquisition date).

Have your formation details handy if you created a U.S. entity (LLC, corp) and be prepared for spelling verification of names and addresses. The IRS agent will assign the EIN during the call if everything checks out; the written confirmation follows by mail per the SS‑4 instructions.

International founders: getting an EIN without an SSN or ITIN

You can obtain an EIN without an SSN or ITIN by submitting Form SS‑4 and using the international path; leave the responsible party identification number blank if none exists. The key is completing SS‑4 accurately and listing a responsible party who controls the entity. See IRS: Instructions for Form SS‑4 for authoritative guidance.

Use a mailing address that can reliably receive IRS letters. If you formed a U.S. entity, match the legal name exactly to formation documents. Be consistent on principal business activity and the start/acquisition date to avoid follow‑ups.

Responsible party and SS‑4 line items

The responsible party is the individual who ultimately controls or directs the entity and its funds or assets. List a real person, not a mailbox or nominee. If the responsible party has no SSN/ITIN/EIN, leave line 7b blank—do not invent numbers or use passport IDs.

On line 9, select the correct entity type (e.g., LLC with member count and tax classification). On line 10, give a plain‑English reason such as “Started a new U.S. LLC with foreign ownership.” Keep activity descriptions on line 16 specific but simple (e.g., “online retail,” “software development”).

What to expect: CP 575 and 147C letters

After assignment, the IRS mails a CP 575 notice confirming your EIN and the legal name as it appears in IRS records. Keep this with your permanent records and share it with banks, processors, and payroll providers as needed.

If you misplace your EIN or a payer asks for official verification, you can request a 147C letter from the IRS, which confirms the EIN and name on file. The 147C is commonly requested during bank KYC, marketplace onboarding, or to resolve a TIN mismatch.

When you need a new EIN (and when you don’t)

You need a new EIN when the underlying taxpayer changes—like converting a sole proprietorship to a corporation, or when certain ownership changes occur in partnerships. You don’t need a new EIN for routine updates such as a name or address change.

Before you assume you need a new number, check the IRS scenarios to avoid unnecessary disruptions to banking and payroll. If you do need a new EIN, apply first, then update your accounts and vendor records with the new number to prevent reporting conflicts.

Common triggers for a new EIN

Common triggers include incorporating a sole proprietorship, adding or removing partners in a way that ends the old partnership, and converting an entity in a way that creates a new taxpayer. Certain bankruptcy reorganizations for sole proprietors can also trigger a new EIN.

Mergers and acquisitions that create a new legal entity or shift the employer of record typically require a new EIN. When in doubt, match the “who files the return now?” test—if that answer changed, you probably need a new EIN.

Situations where you keep your current EIN

You generally keep your EIN when you change your business name, move locations, or adjust your business activity. A corporation electing S‑corp status keeps its EIN; the tax classification changes, not the taxpayer’s identity.

Routine account changes (address, responsible party updates) are handled as updates with the IRS and do not require a new number. Keeping continuity helps maintain clean vendor, payroll, and processor histories.

Federal EIN vs state tax ID: what’s the difference?

A federal EIN identifies your business to the IRS, while state tax IDs register you for state‑level taxes such as sales/use tax and employer payroll withholding. Many businesses need both—EIN for federal filings and banking, and state accounts where you have nexus, employees, or taxable sales.

Choose a federal‑first approach: get the EIN, then register for state accounts where you’ll collect sales tax, withhold payroll taxes, or owe state‑specific excise taxes. Your state Department of Revenue (and labor agency for unemployment) will outline registrations and filing schedules.

Privacy, security, and sharing: W‑9, EIN lookups, and scams

Using an EIN instead of an SSN on Form W‑9 limits unnecessary SSN exposure and helps compartmentalize business identity. EINs aren’t secret, but they also aren’t freely searchable in a way that substitutes for proper verification.

Share your W‑9 only with payers who legitimately need it, store it securely, and rotate access within your team on a need‑to‑know basis. The IRS explains W‑9 purpose and requester obligations in IRS: Instructions for the Requester of Form W‑9, and payers will rely on the TIN you provide for 1099 reporting.

When to provide your EIN and how to store it

Provide your EIN on W‑9s for clients, processors, and marketplaces that issue 1099s, and to banks, payroll providers, and insurers as part of KYC. Avoid emailing unredacted W‑9s broadly; use secure portals or encrypted channels when possible.

Maintain a secure file of your CP 575 and 147C letters, formation documents, and state registrations. Good records make vendor onboarding and audits faster and reduce risk of typo‑driven TIN mismatches.

CPN/EIN misuse risks

Avoid “credit privacy number” or “new credit identity” schemes—misusing or buying CPNs, or misrepresenting an EIN as a personal identifier to obtain credit, can be fraudulent. Some scams also sell “EIN packages” for a fee even though EINs are free from the IRS.

If someone offers to “repair credit” by using a fresh EIN in place of your SSN, walk away. Stick to official IRS channels for EINs and use the number only for legitimate tax and business purposes.

Banking and fintech requirements (SSN vs EIN, payment processors)

Banks and payment processors generally ask for your EIN if you formed an entity, and your SSN for beneficial owners and controllers for KYC. Sole proprietors can often open accounts with an SSN, but many providers prefer or require an EIN to onboard a business brand.

Expect to provide formation documents, EIN verification (CP 575 or 147C), ownership information, and a W‑9. Requirements can be stricter for high‑risk industries, cross‑border flows, or higher processing volumes.

Bank account opening and merchant accounts

For a sole proprietorship with no employees, some banks and processors will accept an SSN and a DBA. Once you form an LLC or corporation—or if you want to separate identity and reduce SSN exposure—an EIN is typically expected.

Merchant accounts and marketplaces (e.g., ecommerce platforms) often ask for an EIN to establish the business taxpayer of record and to issue 1099‑Ks as applicable. Keep your entity name and EIN consistent across bank, processor, and tax records to prevent holds.

BOI reporting and your EIN

Most corporations and LLCs must file Beneficial Ownership Information (BOI) reports with FinCEN starting in 2024, identifying owners and control persons; many small‑business exemptions do not apply. As a rule of thumb, entities formed in 2025 and later must file within 30 days of formation; entities formed in 2024 had 90 days; and entities formed before 2024 had until January 1, 2025 (FinCEN: Beneficial Ownership Information Reporting).

Your EIN and legal name should match across BOI, banking, and IRS records. Inconsistent data can create onboarding delays and compliance flags.

TIN accuracy and compliance: TIN Matching, backup withholding, and penalties

Payers are responsible for accurate TIN/name combinations on 1099s; use IRS TIN Matching to prevent errors. If a payee gives you a missing or incorrect TIN, you may have to withhold 24% from reportable payments under federal backup withholding rules (IRS: Taxpayer Identification Number (TIN) Matching Program; IRS: Backup Withholding).

Mismatches generate IRS notices and can lead to penalties and administrative costs. Build TIN verification into your vendor onboarding and year‑end processes to avoid scrambling during 1099 season.

Using the IRS TIN Matching program

TIN Matching is available through IRS e‑Services to payers who file Forms 1099 (e.g., 1099‑NEC for contractors). You submit name/TIN combinations to confirm they match IRS records before filing.

Use it when onboarding new vendors, when a W‑9 looks incomplete, or before submitting 1099 batches. For sensitive payees, validate early so you can request a corrected W‑9 well before deadlines.

B‑notices and remediation

If the IRS flags a mismatch (CP2100/CP2100A), you must send the vendor a “B‑notice” and solicit a new Form W‑9. If it’s a second notice within three calendar years, the vendor must provide official SSA/IRS validation of the TIN.

Start or continue backup withholding at 24% on reportable payments until the issue is resolved. Document your steps and deadlines carefully—good records can reduce penalty exposure if you’ve followed IRS remediation procedures.

Form SS‑4 tips: line‑by‑line guidance and common errors

Form SS‑4 is straightforward if you align the entity type, responsible party, and reason for applying. The most common issues are responsible party errors, entity mismatches, and vague business descriptions.

Fill names exactly as they appear on formation documents. Keep line 10 specific (e.g., “Started LLC; banking and payroll”), and pick one principal activity on line 16 that best fits. Consistent details across SS‑4, bank applications, and W‑9s prevent verification delays.

Common rejection reasons and how to fix them

Correct by aligning SS‑4 with your legal documents, rewriting line 10 clearly, and re‑faxing or reapplying as appropriate. If the form was signed by a third‑party designee, ensure the designee section is completed so the IRS can discuss the application.

Correcting mistakes after submission

For typos in name or address, contact the IRS to update the EIN record; maintain a copy of the update letter with your files. If a payer needs official verification, request a 147C letter, which confirms the legal name/EIN on file.

If you applied under the wrong entity type and the underlying taxpayer is different, you may need a new EIN. Review the IRS scenarios to confirm before you proceed. Keeping a clean paper trail helps banks and processors reconcile the change quickly.

Related identifiers: ITIN, PTIN, and ATIN

ITINs, PTINs, and ATINs are also TINs but serve different audiences. ITINs are for individuals who aren’t eligible for SSNs, PTINs are for paid tax return preparers, and ATINs are temporary numbers for adopted children pending SSNs. See official details at IRS: Individual Taxpayer Identification Number (ITIN).

Don’t confuse these with EINs: EINs identify businesses, estates, and trusts; ITINs identify individuals for tax filing only; PTINs identify professionals who prepare returns for compensation; ATINs fill a short‑term need during adoption.

ITIN

An ITIN lets individuals who don’t qualify for SSNs file U.S. tax returns and be listed as taxpayers or dependents. ITINs must be renewed periodically if not used on a return, and certain credits (like the Earned Income Credit) aren’t available with ITINs.

Use an ITIN for personal filings—not for business identification. For instructions and renewal rules, see the IRS ITIN page linked above.

PTIN

A PTIN is required for paid tax return preparers and is used to sign returns they prepare for compensation. It’s not a business identifier and doesn’t replace an EIN or SSN for your own filings.

If you pay someone to prepare your return, their PTIN should appear on the return they file on your behalf. PTIN requirements are separate from business registration and payroll obligations.

ATIN

Adoptive parents may need an ATIN to claim a child on a tax return when the adoption is pending and an SSN isn’t yet available. ATINs are temporary and should be replaced with an SSN once assigned.

ATINs don’t authorize work and aren’t used for business identification. They exist to prevent filing delays during the adoption process.

Troubleshooting and next steps: lost EIN, corrections, and support

If you lost your EIN, request a 147C letter to verify your number and legal name for banks, processors, or vendors. Keep your CP 575 and 147C letters, W‑9, and state registrations together and share only with legitimate counterparties who need them.

To apply, correct, or verify: use the official IRS channels to obtain or confirm your EIN, validate payee TINs before filing 1099s, and follow backup withholding rules where required. For entity transparency and KYC alignment, review your BOI obligations and keep data consistent across IRS, banking, and FinCEN records.