Three US tax IDs get confused constantly: the SSN, the ITIN and the EIN. They are not interchangeable. Here is what each one is and who actually needs it.
SSN — Social Security Number
Issued to US citizens and authorized workers. It identifies an individual for work and personal taxes. Most non-residents cannot get one.
ITIN — Individual Taxpayer Identification Number
For individuals who must file or be reported on a US tax return but are not eligible for an SSN — often non-resident owners, spouses or investors. It is for people, not companies.
EIN — Employer Identification Number
A tax ID for a business — your LLC or corporation. You need it to open a US bank account, hire, and file business taxes. Non-residents can get an EIN without an SSN via Form SS-4.
Which do you need?
- Forming a US company: you need an EIN for the entity.
- Filing a personal US return without an SSN: you likely need an ITIN.
- Both can apply — e.g. a non-resident owner with a US LLC may need an EIN for the company and an ITIN for themselves.
Non-resident and stuck on the SS-4? See how to get an EIN without an SSN, or let a CPA & EA team handle it.
How a non-resident gets an ITIN
An ITIN is requested on Form W-7, usually filed together with the US tax return that creates the filing requirement.
You must prove identity and foreign status, typically with a passport, and the IRS accepts certified copies through Certifying Acceptance Agents so you don't have to mail your original passport.
Processing takes several weeks, so apply well ahead of any deadline.
Can one person or business have more than one ID?
An individual should have only one — either an SSN or an ITIN, never both. If you later become eligible for an SSN, you stop using the ITIN.
A business has its own EIN regardless of the owner's personal ID. A non-resident owner might hold an ITIN personally while their LLC holds an EIN.
Mixing these up on forms is a common cause of IRS notices, so it's worth getting right from the start.
A simple way to remember which is which
The three IDs answer three different questions. An SSN identifies a US person. An ITIN identifies an individual who must file US taxes but cannot get an SSN. An EIN identifies a business. You can need more than one at the same time — for example, a non-resident founder often has an EIN for their LLC and an ITIN for themselves.
- SSN — for US citizens and authorised workers; issued by the Social Security Administration.
- ITIN — for individuals with a US tax filing obligation but no SSN; issued by the IRS.
- EIN — for businesses; issued by the IRS and used on returns, payroll, and bank accounts.
How a non-resident gets each one
An EIN is the most accessible: a non-resident can obtain one by filing Form SS-4 with the IRS, typically by fax, even without an SSN or ITIN. An ITIN is obtained by filing Form W-7, usually attached to a US tax return or supported by an approved acceptance agent who can certify your passport.
The IRS explains the EIN process for international applicants on its EIN page, and the ITIN process on its ITIN page. We walk through the founder version step by step in how a non-resident gets an EIN without an SSN.
Common mistakes that cause delays
The most frequent errors we see are applying for the wrong ID, sending an SS-4 with inconsistent entity details, or filing a W-7 without the required supporting documents. Each mistake can add weeks. Getting the entity set up correctly first — see our US company formation service — avoids most of them.
Which ones you will actually use day to day
Your EIN appears on your business tax returns, your bank account, payroll, and any Forms 1099 you issue or receive. Your ITIN appears on your personal US tax return. If you later become eligible for an SSN, it replaces the ITIN. Keeping them straight prevents mismatches that trigger IRS notices.
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Read the guide →Frequently asked questions
What's the difference between an ITIN and an EIN?
An ITIN identifies an individual who must file US taxes but can't get an SSN. An EIN identifies a business entity such as an LLC or corporation.
Can a non-resident get an EIN without an SSN?
Yes. A non-resident can obtain an EIN for a US company by filing Form SS-4, without needing an SSN or ITIN.
Do I need both an EIN and an ITIN?
Possibly. A non-resident who owns a US LLC may need an EIN for the company and an ITIN for themselves if they have a personal US filing requirement.
How long does an ITIN take to get?
Filing Form W-7 with your tax return, processing typically takes several weeks, so apply ahead of any deadline.