Tax identification number (TIN)
is the identifier a tax authority assigns to a person or company — the key payroll and filings run on. Every country names it differently (NI number, Steuer-ID, AHV number’s tax role, Emirates ID contexts), and collecting the right IDs at onboarding is a precondition for correct withholding.
TINs in employment operations
Payroll needs the employee’s TIN for withholding and year-end reporting; banks and authorities increasingly match payments to IDs, and international information exchange (CRS, DAC frameworks) runs on TINs. Missing or wrong IDs produce default — usually punitive — withholding rates and blocked filings.
Onboarding should collect and validate the local TIN, and for cross-border hires, note that a person accumulates one per country of tax contact: the home TIN does not substitute for the host one.
FAQ
What if a new hire has no local TIN yet?
Most systems allow starting employment while the ID is requested, with default tax codes or emergency rates applying until it arrives — then corrections retroactively. Build the application into onboarding day one; emergency rates left running for months are a common overpayment source.
Is the TIN the same as the social security number?
In some countries one number serves both (the Swiss AHV number’s broad use); others keep separate tax and social IDs (Germany’s Steuer-ID vs SV-Nummer). Payroll setups must map which number feeds which reporting stream per country.