What is a Tax Identification Number (TIN)?
As a US taxpayer or a global expat, you've likely heard the term "Tax Identification Number" or TIN tossed around.
But what exactly is it, and why does it seem to appear in every tax conversation? Whether you're filing taxes, opening a bank account, or dealing with IRS paperwork, a TIN is your VIP pass to navigate the tax world.
Let’s dive into the details and explore why a TIN matters, the types available, and how to obtain one.
What is a TIN?
A Tax Identification Number (TIN) is a nine-digit number assigned to individuals, businesses, and other entities for identification in tax-related matters.
Think of it as your personal “tax fingerprint.” It’s required for reporting income, filing returns, and interacting with the IRS.
Types of TINs
1. Social Security Number (SSN)
The SSN is the most common TIN issued by the Social Security Administration (SSA). It’s primarily for US citizens and eligible residents.
If you’ve ever worked in the US, your SSN is already your TIN.
- Who needs it? US citizens, permanent residents, and certain non-citizens authorized to work.
- How to get it? Complete Form SS-5 through the SSA.
2. Individual Taxpayer Identification Number (ITIN)
An ITIN is for individuals who need to pay US taxes but aren’t eligible for an SSN.
This includes non-resident aliens, spouses, and dependents.
Key points:
- ITINs start with "9" and are primarily used for tax filing.
- They expire if not used for three consecutive years.
- An ITIN does not authorize work in the US
Application process: Submit Form W-7 to the IRS, along with proof of identity and foreign status. This can be done via mail, IRS offices, or through a Certified Acceptance Agent.
3. Employer Identification Number (EIN)
Businesses and organizations use an EIN, often referred to as a “business TIN.”
It's essential for entities engaging in taxable activities like hiring employees or filing corporate taxes.
Who needs it?
- Corporations
- Partnerships
- Nonprofits
- Self-employed individuals opening business accounts
How to get it? Apply online via the IRS website or by submitting Form SS-4.
4. Global TINs: How they differ
For expats and international taxpayers, understanding global TINs is crucial.
Other countries issue TINs under different names and formats.
| Country/Region | TIN Equivalent | Issued By |
|---|---|---|
| United States | SSN, ITIN, EIN | IRS / SSA |
| European Union | National Tax Number (varies) | Respective Tax Authorities |
| Canada | Social Insurance Number (SIN) | Canada Revenue Agency |
| United Kingdom | Unique Taxpayer Reference | HM Revenue and Customs (HMRC) |
NOTE! Many European countries use TINs to harmonize tax reporting across the EU.
Why is a TIN important?
A TIN is more than just a number – it’s a gateway to financial and legal compliance.
Key uses of a TIN:
- Filing tax returns.
- Opening US bank accounts.
- Claiming tax treaty benefits (for expats).
- Conducting business transactions.
- Reporting foreign assets (e.g., FBAR or FATCA compliance).
NB! Without a TIN, you’re essentially locked out of participating in the financial system or complying with tax laws.
How to validate a TIN
Not all TINs are created equally, and validating one can save you from future headaches.
- For US TINs: Use IRS validation tools or consult a tax professional.
- For international TINs: Many countries, including EU nations, provide online validation services.
✔️Pro tip: Validation tools only verify the number format, not the identity of the person or entity.
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How to apply for a TIN
Applying for an SSN
- Complete Form SS-5.
- Submit proof of identity, age, and work authorization.
- File the application with the SSA in person or by mail.
Applying for an ITIN
- Fill out Form W-7.
- Provide original documents proving identity and foreign status.
- Mail the form to the IRS or use a Certified Acceptance Agent.
Applying for an EIN
- Complete Form SS-4 online or by mail.
- Provide your business name and type.
- Receive your EIN instantly (if applying online).
TINs in the digital economy
Modern financial platforms like Stripe and PayPal require TINs to ensure compliance with US tax laws.
Businesses using these platforms must provide an EIN or SSN for tax reporting purposes.
Bottom line
Whether you’re an expat navigating international tax rules or a US resident filing your annual return, a TIN is essential for staying compliant and avoiding penalties.
If you don’t have the right TIN – or if yours has expired – don’t wait to resolve the issue.
As we like to say in the tax world,
"Numbers never lie – but they sure can be confusing without the right guidance!"
Taxes are complicated
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FAQ
Yes! If you’re a US citizen or resident living abroad, you still need a TIN typically an SSN or ITIN to file federal taxes. It’s also required for fulfilling obligations like FATCA (Foreign Account Tax Compliance Act) and FBAR (Report of Foreign Bank and Financial Accounts) reporting.
If your ITIN expires, the IRS will reject your tax return if you claim certain tax benefits like the Child Tax Credit or the Earned Income Tax Credit. To avoid delays, renew your ITIN by submitting Form W-7 before filing your taxes.
It depends. An individual can have one SSN, and if they run a business, they may also have an EIN for business purposes. However, a single taxpayer should not have multiple SSNs or ITINs.
SSN: For US citizens and eligible residents.
ITIN: For non-citizens not eligible for an SSN, like foreign nationals with US tax obligations.
EIN: For businesses, nonprofits, and self-employed individuals needing a business TIN.
You need an ITIN if you’re required to file a US tax return but don’t qualify for an SSN. For example, non-resident aliens earning US income or dependents of US taxpayers often need ITINs.
Yes. A TIN is often required even if you’re not earning income, such as when claiming tax treaty benefits or reporting investments.
No. An ITIN only allows you to fulfill tax obligations. It does not authorize employment or grant Social Security benefits.
Yes, if a foreign business operates in the US, hires employees, or files US taxes, it must obtain an EIN.
SSN: Request a replacement card through the Social Security Administration (SSA).
ITIN: Contact the IRS directly.
EIN: Refer to the confirmation notice you received when you applied or contact the IRS for assistance.
Yes. If you don’t use your ITIN on a federal tax return for three consecutive years, it will expire. You can renew it by submitting Form W-7 with updated documentation.
If your child qualifies for an SSN, apply through the SSA using Form SS-5. If not, you can apply for an ITIN by filing Form W-7 with proof of identity and foreign status, typically alongside your tax return.
Filing without a valid TIN can result in:
- Rejection of your tax return.
- Inability to claim certain tax credits or deductions.
- Penalties for late filing or incorrect information.
The processing time depends on the type of TIN:
- SSN: Typically issued within two weeks by the SSA.
- ITIN: Usually takes 7-11 weeks after submitting Form W-7 to the IRS.
- EIN: Instant if applied online; 4-5 weeks if applying by mail.