A direct, accurate answer depends on which Tax Identification Number (TIN) you’re referring to and which country you’re in. Here’s a practical guide to finding the right number:

• United States
  • Individual: Social Security Number (SSN) is your personal TIN. Find it on your Social Security card or on tax documents (Form 1040, notices). If you’ve lost it, contact the Social Security Administration or IRS for guidance.
  • Employer/Business: Employer Identification Number (EIN) is used for business taxes. It’s on IRS notices, the EIN confirmation letter, and business tax filings (e.g., Form 941, Form 1120). If you’ve lost it, contact the IRS.
  • ITIN: Individual Taxpayer Identification Number used for tax processing when no SSN is available; found on tax returns and IRS correspondence. You can request assistance from the IRS if needed.
• Other countries (common equivalents)
  • Germany: Steueridentifikationsnummer (11 digits) found on the tax assessment or official letters from the tax office.
  • Austria: 9-digit Steuernummer, obtainable from the local Finanzamt or Finanzonline, and sometimes shown on income tax notices.
  • Netherlands: BSN (citizen service number) used for tax and government services; located on official documents.
  • Other EU countries: Many use a TIN similar to what’s described in national tax documents; location typically on tax assessments or letters from the tax authority.

What to do next

• Determine the country and whether you need an individual TIN (SSN/ITIN/etc.) or a business TIN (EIN or equivalent).
• Check the following first:
  • Official notices from the tax authority or social security agency.
  • The tax return forms or correspondence you’ve received in the mail or online account.
  • Your employer payroll documents or business filings.
• If you cannot locate it:
  • For individuals, contact the relevant tax authority or social security agency to verify identity and retrieve or reissue the number.
  • For businesses, contact the tax authority’s business/EMB office or use their online portals to recover or apply for an EIN or equivalent.

If you share your country and whether you’re looking for an individual or business TIN, a precise, step-by-step path can be tailored.