How to conduct a payroll audit in seven steps

Executive overview

Payroll is typically an organisation's largest expense, and errors are both common and costly. Waiting for employees or regulators to surface mistakes is too late.

A seven-step internal audit process lets HR teams catch inaccuracies, stay compliant, and fix problems before they escalate. The process covers workforce sampling, employee data, hours, variable pay, withholdings, reconciliation, and follow-through.

Proactive audits are cheaper than reactive corrections — run them at least once a year.

Why regular payroll audits matter

• Errors in automated payroll compound: one bad input generates repeated bad paychecks
• Compliance failures attract Department of Labor investigations and IRS scrutiny
• Audits surface fraud, though errors are far more common
• Employees notice underpayments immediately; government notices repeated tax inconsistencies eventually

Seven steps to audit payroll

1. Define scope and timeframe — sample a percentage of employees; cover at least two consecutive pay periods; audit at minimum annually
2. Review employee information — check for pay rate changes (promotions), W-4 updates (life events), and residency changes that affect tax jurisdiction
3. Verify hours worked and time off — confirm time-and-attendance records for hourly workers; account for PTO used by hourly and salaried staff
4. Note variable and off-cycle pay — verify overtime at 1.5× rate; review bonuses, commissions, shift differentials, hazard pay, signing bonuses, and payroll corrections; include off-cycle runs
5. Recalculate withholdings and deductions — update calculations for W-4 or residency changes; verify benefit deductions match enrollment; check HSA, FSA, and 401(k) contribution changes
6. Reconcile with accounting, bank, and tax records — confirm payroll totals appear in the general ledger and bank statements; verify tax deposits were correct and timely using Form 941
7. Analyse, report, and improve — present findings to leadership with specific improvement proposals; communicate changes clearly to the workforce

Five common payroll mistakes

• Worker misclassification — designating a non-exempt employee as exempt denies overtime; treating an employee as a contractor denies legal protections; classification is not fully at the employer's discretion
• Miscalculating pay — base pay, supplemental wages (bonuses, commissions), reimbursements, stipends, and wage garnishments (debt, tax liabilities, child support) must all be correct
• Missing pay deadlines — organisations must meet scheduled paydays consistently; the four main schedules are weekly, bi-weekly, semi-monthly, and monthly; some offer on-demand pay
• Neglecting tax forms — W-4s must stay current in the payroll system; W-2s and 1099s must be issued after year-end and match payroll records; Form 941 is due quarterly
• Incomplete records — the FLSA requires payroll records to be retained for three years; gaps create exposure during external audits and can result in fines