Payroll Parallel Test

What is a Payroll Parallel Test?

A payroll parallel test is a validation process where payroll is calculated simultaneously in both old and new systems to verify accuracy before fully transitioning to new software.

During this testing phase, organizations run identical payroll inputs through both systems, then compare outputs including gross pay, deductions, taxes, net pay, and employer costs. Discrepancies are investigated and resolved before going live.

Parallel testing identifies configuration errors, validates calculation accuracy, builds user confidence, and mitigates implementation risks. This critical quality assurance step typically runs for one to three payroll cycles, ensuring the new system produces correct results before decommissioning legacy systems. Thorough parallel testing prevents costly payroll errors and employee dissatisfaction.