ITIN vs TIN: What Is the Difference in 2026?

What Is a TIN and Why Does the IRS Use This Term?

TIN stands for Tax Identification Number. The IRS defines it in Internal Revenue Code Section 6109 as any identifying number assigned to a person for federal tax administration purposes. Every individual and entity that files taxes, reports income, or claims benefits under the US tax code must have a TIN. The term appears on hundreds of IRS forms including the W-9, W-8BEN, 1099 series, and every version of the 1040.

The confusion arises because people often use "TIN" as if it refers to a specific number. It does not. When a form asks for your TIN, it is asking for whichever taxpayer identification number you have been assigned. For US citizens, that is their SSN. For businesses, that is their EIN. For non-resident aliens without work authorization, that is their ITIN. All 3 are TINs.

What Are the 3 Main Types of TINs?

The IRS issues 3 primary taxpayer identification numbers. Each serves a different population and purpose. Here is a complete comparison.

Who Gets an SSN vs an ITIN vs an EIN?

The distinction is straightforward. An SSN goes to individuals authorized to work in the United States: US citizens at birth, naturalized citizens, lawful permanent residents (green card holders), and certain visa holders with work authorization (H-1B, L-1, O-1, etc.). The Social Security Administration issues approximately 5.5 million new SSNs per year.

An ITIN goes to individuals who have US federal tax obligations but cannot get an SSN. This includes non-resident aliens earning US-source income, foreign owners of US LLCs, spouses or dependents of US citizens or residents claimed on tax returns, and anyone claiming tax treaty benefits. The IRS has approximately 4.4 million active ITINs as of 2024 data. For a deeper comparison, read our ITIN vs SSN complete comparison.

An EIN goes to business entities: corporations, LLCs, partnerships, sole proprietorships with employees, trusts, estates, and nonprofits. Any entity that pays employees, files certain tax returns, or withholds taxes on income paid to non-resident aliens needs an EIN. For details on when you need both, see our ITIN vs EIN guide.

How Do Multiple TINs Work Together?

Many people hold more than one type of TIN simultaneously. A US citizen who owns a business has both an SSN and an EIN. A non-resident alien who owns a US LLC has both an ITIN and an EIN. This is normal and expected by the IRS. Each TIN serves a distinct purpose in the tax system.

The one combination the IRS does not allow is holding both an SSN and an ITIN at the same time. If you previously received an ITIN and later become eligible for an SSN (through marriage to a US citizen, obtaining a green card, or receiving work authorization), you must notify the IRS by visiting an SSA office and contacting the IRS to merge your records. The IRS will retire your ITIN and transfer your tax history to your new SSN. Learn more in our guide on whether an ITIN can become an SSN.

When Do You Use Each Type of TIN on Tax Forms?

Tax forms ask for a "TIN" in specific contexts. The W-9 form asks US persons for their TIN, which is either an SSN or EIN. The W-8BEN form asks non-US persons for their foreign TIN and optionally their US TIN (ITIN). The 1040-NR asks for your ITIN in the SSN field if you do not have an SSN. Form 1040 uses your SSN.

For business forms like the 1065 (partnership return), 1120 (corporate return), or 941 (employer quarterly return), you use the EIN. For personal employment taxes reported on a W-2, the employer uses the EIN and the employee uses their SSN or ITIN. Understanding which TIN goes where prevents processing delays and IRS notices.

What Are the 5 Most Common TIN Misconceptions?

Confusion about TINs leads to application errors, filing mistakes, and unnecessary delays. Here are the 5 most frequent misunderstandings.

• Misconception 1: "TIN" means one specific number. TIN is a category, not a number. There is no standalone "TIN" you can apply for. You apply for an SSN, EIN, or ITIN specifically.
• Misconception 2: An ITIN can replace an SSN for employment. It cannot. An ITIN is explicitly not valid for employment authorization. Only an SSN authorizes you to work in the United States. Using an ITIN for employment is a violation of federal law.
• Misconception 3: You need an SSN to start a US business. You do not. Non-resident aliens can obtain an EIN for a US LLC or corporation without an SSN. You can use an ITIN as the responsible party's TIN on the EIN application, or apply by fax/mail if you have neither.
• Misconception 4: A TIN proves immigration status. No TIN of any kind establishes immigration status, work authorization, or residency rights. The IRS explicitly states this in IRS Publication 1915 regarding ITINs. TINs are for tax administration only.
• Misconception 5: All TINs last forever. SSNs and EINs do not expire. ITINs do expire after 3 consecutive years of non-use on a federal tax return, or when the IRS cycles out specific middle-digit cohorts. See our ITIN expiration guide for details.

How Do You Get the Right TIN for Your Situation?

For an SSN, visit your local Social Security Administration office with your birth certificate or passport, immigration documents proving work authorization, and a completed SS-5 form. Processing takes 2 to 4 weeks by mail or you receive it at the appointment.

For an EIN, apply online at IRS.gov using Form SS-4. If you have an SSN or ITIN, you can complete the application online and receive your EIN immediately. If you have neither, submit Form SS-4 by fax and receive your EIN within 4 business days.

For an ITIN, submit Form W-7 to the IRS. The most efficient method is through a Certifying Acceptance Agent like itin.so, which lets you keep your passport and handles the entire process remotely. Read our complete guide to applying for an ITIN online in 2026 for the full 5-step process.

Which TINs Do International Entrepreneurs Need?

If you are a non-US resident starting a US business, you typically need 2 TINs: an ITIN for your personal tax obligations and an EIN for your business entity. The ITIN identifies you as an individual taxpayer. The EIN identifies your LLC, corporation, or partnership. Both are required for full tax compliance.

Many non-US entrepreneurs also need these TINs for practical business operations. Banks, payment processors, and platforms like Shopify, Etsy, and Upwork require a TIN for tax reporting. Without the correct TIN, these platforms withhold 24% to 30% of your earnings as backup withholding.