The shortest version: an EIN identifies your business to the IRS. An ITIN identifies you as an individual when you are not eligible for a Social Security Number. They are not interchangeable, and most non-resident founders running a U.S. LLC need both — for different reasons, at different points in the workflow. This guide explains exactly when each one is required, what happens if you have the wrong one, and which to apply for first.
What an EIN Is
An Employer Identification Number is a nine-digit number the IRS issues to a business entity. It is the entity's federal tax ID. You need an EIN for any U.S. business that:
- Has employees
- Files U.S. business tax returns
- Opens a U.S. business bank account
- Hires U.S. contractors and issues Form 1099
- Operates as a multi-member LLC or any corporation
Even single-member LLCs without employees apply for an EIN — banks require it for business account opening, and it keeps the owner's personal tax ID off business filings.
EIN is issued via Form SS-4. Applicants with a Social Security Number can apply online and get a number instantly. Applicants without an SSN — virtually all non-resident founders — apply by fax or mail, with a typical IRS processing time of 3 to 5 weeks.
What an ITIN Is
An Individual Taxpayer Identification Number is a nine-digit number the IRS issues to an individual who has a U.S. tax filing obligation but is not eligible for a Social Security Number. Non-resident aliens, foreign founders whose income flows through to a U.S. tax return, spouses and dependents of U.S. taxpayers — all need an ITIN if they have to interact with the U.S. tax system.
ITIN is issued via Form W-7, submitted with a U.S. federal tax return (or, in limited circumstances, on its own). You need an ITIN to:
- File a U.S. tax return as a non-resident individual
- Be claimed as a dependent or spouse on a U.S. return
- Claim a tax treaty benefit
- Open certain personal U.S. bank accounts where the SSN field is required
Through a Certified Acceptance Agent, ITIN processing typically completes in 5 to 10 business days. Filed by mail directly to the IRS, the same application takes 8 to 14 weeks.
When You Need Both
Most non-resident founders operating a U.S. LLC need both. Here is why.
The LLC needs an EIN. The bank requires it, the IRS requires it, and any contract counterparty issuing you a 1099 will request it.
The individual owner needs an ITIN — but only if there is a personal U.S. tax filing obligation. For most single-member foreign-owned LLCs with no U.S. trade or business and no U.S.-source income, there is no individual filing obligation, and the owner does not technically need an ITIN.
Where the ITIN matters:
- Multi-member LLCs that issue K-1s to non-resident members — each member needs an ITIN
- Foreign founders earning U.S.-source income outside the LLC (consulting fees billed personally, rental income from U.S. real estate, royalties)
- Foreign founders who want to be on certain personal banking products that do not accept "no taxpayer ID" applicants
- Spouses of U.S. citizens or residents filing joint returns
If you are running a single-member LLC selling digital products into the U.S. from abroad, with no other U.S. ties, you may need only the EIN.
The Comparison at a Glance
| EIN | ITIN | |
|---|---|---|
| Issued to | Business entity | Individual |
| IRS form | SS-4 | W-7 |
| Purpose | Business tax ID | Individual tax ID for those ineligible for an SSN |
| Required for U.S. business bank account | Yes | No (used for personal account) |
| Required for personal U.S. tax return | No | Yes (if you have a filing obligation) |
| Processing time, non-resident through CAA | Days | 5 to 10 business days |
| Processing time, by mail to IRS | 3 to 5 weeks | 8 to 14 weeks |
| Renewal required | No | Yes, if unused for 3 consecutive years |
Common Misconceptions
"I have an EIN, so I don't need an ITIN." The EIN is for the entity. If you, the individual owner, have a personal U.S. tax filing obligation, you still need an ITIN. The EIN does not satisfy individual filing requirements.
"I'll just use my LLC's EIN on my personal return." You can't. The IRS uses different identifiers for entity and individual filings, and a return submitted with an EIN in the SSN/ITIN field is rejected outright.
"My foreign tax ID is fine." It isn't, for U.S. purposes. The IRS accepts only SSNs and ITINs as taxpayer identification on U.S. returns and W-7 / W-8 forms. Your foreign TIN is captured on Form W-8BEN as supplementary information but doesn't replace an ITIN where one is required.
"I'll skip the ITIN since I'm not filing." If you have a U.S. filing obligation and skip the ITIN, you create back-filing problems and potential withholding agent issues. If you genuinely have no filing obligation, you do not need an ITIN — confirm with an attorney that you are in that category.
Which to Apply for First
Sequence matters, especially when you are starting fresh.
For a non-resident founder forming a U.S. LLC:
- Form the LLC (state filing)
- Apply for the EIN for the LLC (Form SS-4)
- Open the business bank account using the EIN
- If individual filing is required, apply for the ITIN (Form W-7)
Applying for the ITIN before the LLC is unnecessary — and applying for an EIN before the LLC exists doesn't work because the SS-4 asks for the entity's formation state and date.
For non-resident individuals with personal U.S. tax filings (rental property, royalties, capital gains):
- Apply for the ITIN with the W-7 attached to your first U.S. tax return
- No EIN required unless you later form a U.S. business entity
When Both Get Filed Together
itin.net bundles EIN and ITIN applications for clients forming a U.S. LLC because the document sets overlap heavily — passport, ID verification, supporting documentation — and filing both at once is faster than filing each in isolation. If you know you need both, do them in one engagement rather than two.
If you are not sure which you need, the question is almost always "what U.S. filing obligation will I have in the next 12 months?" Answer that first, and the EIN-vs-ITIN question answers itself.
