Why it matters
A payroll register is output, not proof. Under IRS recordkeeping guidance, employment tax records, including copies of Forms W-4, are kept at least four years after the fourth-quarter filing. DOL says payroll records are kept three years and wage-computation records two. A firm without the inputs cannot defend a return.
Example
A restaurant client's server shows $0 withholding adjustments. Ask for the employee's current Form W-4 (the IRS encourages a new one each year). If a new employee gives no completed 2026 Form W-4, Publication 15 says to treat them as Single or Married filing separately in Step 1(c), with Steps 2, 3 and 4 blank. For an existing employee, keep applying the most recent valid Form W-4 on file. For tips, request the monthly statement due by the 10th; months under $20 need no report.
Related terms
Questions about Payroll source documents
Is a payroll register a source document?
No. The register is a summary the payroll system produces from the inputs. The source documents are the inputs behind it, such as the Form W-4, timecards, tip statements and the written approval for a pay-rate change. Keep both, but when a number is questioned, the register alone does not support it.
How long should a firm keep payroll source documents?
The IRS says to keep employment tax records at least four years after filing the fourth quarter for the year, and that includes copies of Forms W-4. The Department of Labor says payroll records are kept three years and wage-computation records such as timecards two years. Use the longest period that applies.