Employee and Contractor Tax IDs
Ensure accurate tax reporting by collecting valid Tax Identification Numbers for employees and contractors.
Collecting the correct tax identification number for workers
To ensure accurate year-end reporting—W-2s for employees and 1099s for contractors—Check requires a valid Tax Identification Number (TIN) for each worker. A TIN can refer to several types of identifiers, including:
- Social Security Number (SSN)
- Employer Identification Number (EIN)
- Individual Taxpayer Identification Number (ITIN)
Each worker type has different requirements.
Employees
W-2 employees must have a valid Social Security Number (SSN) to be eligible for U.S. employment. This is mandated by both the Department of Homeland Security (as part of the Form I-9 process) and the IRS. According to IRS guidance:
You are required to get each employee's name and Social Security number (SSN) and to enter them on Form W-2... Do not accept an ITIN in place of an SSN for employee identification or for work. IRS guidance on hiring employees
Employees with ITINs are not eligible for W-2 reporting. If an SSN is not available at the time of onboarding, partners may enter a placeholder (e.g., all zeroes) to temporarily unblock setup. The SSN must be updated in the system as soon as it becomes available to avoid failed year-end filings.
Note: If an SSN is not provided and the employee has an ITIN on file, the filing will fail. Check previously supported ITINs for W-2 workers, but these are no longer considered valid for employee records.
Partners can request a report of employees with invalid or missing SSNs by submitting a ticket through Zendesk.
Contractors
Check supports paying both individual and business contractors:
- Individuals may provide either an SSN or an ITIN.
- Business entities must provide a valid Federal Employer Identification Number (FEIN) and legal business name.
You can find more detail in the IRS Instructions for Forms 1099-MISC and 1099-NEC (page 10).
Last updated on June 6, 2025