TIN Number
What is a TIN number and which TINs do employers use?
A Taxpayer Identification Number (TIN) is a generic term for any of several tax-related ID numbers issued by the IRS or SSA. Employers commonly work with three TIN types: Social Security Number (SSN) for employees, Employer Identification Number (EIN) for the business itself, and Individual Taxpayer Identification Number (ITIN) for non-resident aliens or others not eligible for an SSN. TINs are required on W-2s, 1099s, I-9s, and most other tax forms.
TIN is the umbrella term that covers several specific tax ID numbers, and getting the right one in the right place is what makes year-end tax reporting work. The most common confusion is between SSN (employee personal ID), EIN (employer business ID), and ITIN (for non-residents who can't get an SSN). Each appears in different boxes on different forms, and a mismatch produces IRS B-notices that take weeks to resolve.
The Three TIN Types Employers Use
Social Security Number (SSN): nine-digit personal ID issued by SSA, used for employees on W-2 and I-9. Employer Identification Number (EIN): nine-digit business ID issued by IRS, used by the employer on all federal tax filings. Individual Taxpayer Identification Number (ITIN): nine-digit ID for non-residents, used on 1099s and tax returns when SSN isn't available.
Where Each TIN Appears
SSN: W-2 employee box, I-9 Section 1, W-4. EIN: W-2 employer box, all 1094/1095 forms, all federal tax deposits. ITIN: 1099 recipient box for non-resident contractors, individual tax returns.
TIN Verification and B-Notices
The IRS matches TINs against names on tax filings. Mismatches produce B-notices to the employer, requiring W-9 collection from the affected payee. Persistent mismatches can lead to backup withholding requirements. Use IRS TIN matching service (e-Services) before filing 1099s.
Keeping TINs Clean Across Your HR and Payroll Systems
Verify SSNs at hire through E-Verify or SSA. Maintain accurate EIN records in payroll. Collect W-9s for all 1099 recipients. Audit annually before year-end. For multi-entity employers, ensure each entity uses its own EIN correctly. IRS reference: irs.gov/taxpayer-identification-numbers.
.svg)
.svg)