EIN vs ITIN vs SSN: the US tax identification numbers explained
ITIN vs SSN without confusion: which number a non-resident needs, when it matters for your LLC and how Exentax coordinates it without sending your physical passport.
The ITIN has 9 digits and is issued in 7 to 11 weeks, while the SSN has 9 digits and is granted only to US legal residents.
EIN, ITIN, SSN. US tax identification numbers can be confusing. Here's a clear guide to what each one is, whether you need them, and how to get them.
Social Security Number (SSN)
An SSN is the personal tax identification number for US citizens and certain US residents (green card holders, some visa holders).
Format: XXX-XX-XXXX
Who needs it: US citizens and eligible US residents.
Do you need one? As a non-resident LLC owner, you almost certainly don't have an SSN and don't need one for your LLC operations. The SSN is not required for forming an LLC, opening Mercury, or filing Form 5472.
Employer Identification Number (EIN)
The EIN is the business tax ID for your LLC. essential for every aspect of LLC operation. Think of it as your company's Social Security Number.
Format: XX-XXXXXXX
Who needs it: Every US business entity, including every LLC.
Do you need one? YES. absolutely required. Without an EIN, you cannot:
- Open a bank account (Mercury, Relay)
- File <a href="https://www.irs.gov" target="_blank" rel="noopener">IRS</a> forms (Form 5472, Form 1120)
- Set up Stripe or PayPal Business
- File the BOI Report with <a href="https://www.fincen.gov" target="_blank" rel="noopener">FinCEN</a>
- Work with US clients (they need your EIN for W-8BEN-E)
How to get it: At Exentax, we obtain your EIN as part of the formation package. For non-residents, the process involves filing Form SS-4 with the IRS (4-8 weeks by mail, faster by fax). You cannot apply online without a US SSN or ITIN.
The EIN confirmation letter (CP 575): Once approved, the IRS sends this letter confirming your EIN. Mercury specifically requests it. Keep it safe — digital and physical copies.
Individual Taxpayer Identification Number (ITIN)
An ITIN is issued by the IRS to individuals who need to file US tax returns but don't have (or aren't eligible for) an SSN.
Format: 9XX-XX-XXXX (always starts with 9)
Do you need an ITIN as a non-resident LLC owner?
Probably not, for most of our clients. If your LLC has no US-source income and you're not filing a US personal tax return, you typically don't need an ITIN.
When you might need an ITIN:
- PayPal Business requires the owner's ITIN for personal identity verification (in addition to the LLC's EIN)
- Your LLC has US-source income and you need to file Form 1040-NR personally
- Specific treaty benefit claims that require personal filing
- Applying for certain US financial products that require personal tax ID
How to get an ITIN:
- File Form W-7 with supporting documents
- Must be submitted with a US tax return or a certified exception
- Processing time: 7-11 weeks (sometimes longer)
- Requires certified copies of identification documents (passport)
- Can be filed through a Certifying Acceptance Agent (CAA) who can verify your documents
Important ITIN notes:
- ITINs expire if not used on a federal tax return for 3 consecutive years
- Renewal requires the same process as initial application
- The ITIN is for tax purposes only, not a work permit or immigration status
Summary table
| ID Type | For whom | Format | Required for LLC? | How to get |
|---|---|---|---|---|
| EIN | Business entity | XX-XXXXXXX | Yes; essential | Form SS-4 (Exentax handles) |
| SSN | US citizens/residents | XXX-XX-XXXX | No | Not applicable |
| ITIN | Individuals without SSN | 9XX-XX-XXXX | Maybe (PayPal, specific cases) | Form W-7 + tax return |
Common confusion points
"Do I need an ITIN to form an LLC?" No. You need an EIN (for the LLC), not an ITIN (for you personally).
"Mercury requires my SSN." No. Mercury accepts non-US residents without SSN. You provide your passport and foreign tax ID instead.
"PayPal won't let me register without SSN/ITIN." PayPal Business may require the owner's ITIN. If PayPal is essential for your business, we can guide you through the ITIN application process.
"Can I use my EIN instead of ITIN?" No — they serve different purposes. EIN identifies your business. ITIN identifies you personally. Some platforms need both.
The complete tax ID comparison
| Feature | EIN | ITIN | SSN |
|---|---|---|---|
| Full name | Employer Identification Number | Individual Taxpayer ID Number | Social Security Number |
| Format | XX-XXXXXXX | 9XX-XX-XXXX | XXX-XX-XXXX |
| Issued to | Business entities | Non-resident individuals | US citizens/permanent residents |
| Purpose | Entity identification, banking, tax filing | Personal US tax filing | Employment, benefits, identification |
| Required for LLC? | YES (always) | Sometimes (PayPal, some banks) | NO (non-residents can't get one) |
| Processing time | 4-8 weeks (by fax) | 7-11 weeks | N/A for non-residents |
| Cost | Free | Free (Form W-7) | N/A |
| Renewal | Never expires | Must be used every 3 years or it deactivates | N/A |
When your LLC needs an ITIN (and when it doesn't)
You need an ITIN if:
- You want to use PayPal Business (requires owner's ITIN)
- You sell on Amazon.com as a third-party seller (requires ITIN for tax reporting)
- You have US-source income subject to withholding (royalties, rents)
- You want to file a US personal tax return (rare for non-residents)
You do NOT need an ITIN if:
- You use Mercury for banking (EIN is sufficient)
- You use Stripe for payments (EIN + passport is sufficient)
- You use Wise Business for currency conversion (EIN is sufficient)
- You have no US-source income (most digital service providers)
- You don't sell on US marketplaces
How to get an ITIN
- Complete IRS Form W-7
- Attach a valid federal tax return (or qualify for an exception)
- Include certified passport copies or use a Certifying Acceptance Agent (CAA)
- Mail to IRS ITIN Operations, Austin, TX
- Wait 7-11 weeks for processing
At Exentax, we can coordinate ITIN applications for clients who need them, working with Certifying Acceptance Agents so you never have to mail your original passport.
FAQ on EIN vs ITIN vs SSN: the US tax identification numbers explained
How long does each ID take to obtain?
| ID Type | Processing time | Method | Expedite option |
|---|---|---|---|
| EIN | 4-8 weeks | Form SS-4 by fax/mail | Fax is faster (~2-4 weeks) |
| ITIN | 7-11 weeks | Form W-7 by mail | Use CAA to avoid mailing passport |
| SSN | N/A for non-residents | Not applicable | Not applicable |
Can I start my LLC before getting the EIN?
Yes. The LLC is formed first (state filing), then the EIN is applied for. You can't open bank accounts until the EIN is received, but the LLC legally exists from the moment the state approves the Articles of Organization.
What if my EIN letter (CP 575) gets lost?
You can request a replacement from the IRS by calling the International line. Alternatively, Exentax can request a verification letter (147C letter) that serves the same purpose. Your EIN number itself never changes.
Can I use my foreign tax ID instead of an ITIN?
For most LLC operations, yes. Mercury accepts foreign tax IDs. Stripe accepts passport numbers. The EIN covers the LLC's identity. An ITIN is only needed for specific platforms (PayPal, Amazon) that require personal US tax identification.
Does the EIN expire?
No. Once issued, an EIN is permanent — it never expires and never changes. Even if you dissolve the LLC, the EIN remains associated with it in IRS records.
Can I have multiple EINs?
Each LLC gets exactly one EIN. If you have multiple LLC, each one has its own EIN. You cannot share EINs between entities.
To keep going on this thread, <a href="/en/blog/llc-mistakes-irs-banking-and-asset-protection">Common LLC problems and how to avoid them: lessons from real clients</a> fills in a nuance this guide only touched on.
An ITIN is useful when it fits a valid tax or financial profile. Before applying, confirm why it is needed, which documents support the case, how it connects to the LLC or owner and what it will not do: it is not an SSN, immigration status or credit shortcut.
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- Mercury: the question is not brand recognition; it is whether it supports the real flow. The LLC needs documents, activity explanation and a banking alternative if a review pauses the account.
- Payoneer operates through European entities (Payoneer Europe Ltd, Ireland) that are also in scope for CRS for clients resident in participating jurisdictions.
FinCEN and IRS reporting requirements moved recently; the current state is:
- EIN and notice. Without an EIN you cannot file Form 5472. The IRS does not warn before imposing penalties; you find out when an EIN is flagged or a later filing is rejected. At Exentax we map the exposure early, prepare the reasonable-cause file and reduce avoidable escalation before the authority controls the timeline.
Who needs an ITIN?
An ITIN should start from a valid federal tax reason, not from a vague wish to “access the US system”. When the reason is clear, the documents, W-7 route and timeline are much easier to control.
ITIN vs SSN: key differences
The numbers and the calendar matter - get either wrong and the rest unravels.
Step 1: Prepare Form W-7
Form W-7 is where many files become weak: the name, address, treaty or exception basis, identification document and tax purpose must support the same story.
Step 2: Gather supporting documentation
If it is not clean here, every downstream assumption becomes negotiable in front of the authority.
Step 3: Include a tax return
The attached return or exception package is not a formality. It is the evidence that the IRS is being asked for an ITIN for a concrete tax purpose, not for an undefined financial objective.