A paycheck may look consistent from month to month, but the amount withheld for federal income tax may no longer match a taxpayer’s situation. Changes such as starting a second job, getting married, welcoming a child, retiring, buying a home, or experiencing a major income shift can affect how much tax should be withheld. Reviewing withholding during the year can help reduce the risk of an unexpected tax bill or a penalty when filing.

The IRS Tax Withholding Estimator allows eligible workers and retirees to compare expected tax liability with the amount currently being withheld. Before using it, taxpayers should gather recent pay stubs, information about a spouse’s income when filing jointly, the most recent federal tax return, and records related to deductions, credits, self-employment income, or other payments. The results can help a taxpayer decide whether to submit an updated Form W-4 to an employer or Form W-4P to a pension provider.

Withholding should be reviewed early in the year and again after a major life or income change. Taxpayers with self-employment, investment, rental, or gig income may also need to consider estimated tax payments because federal income tax operates on a pay-as-you-go basis. Checking these details before year-end can support better cash-flow planning and make tax filing more predictable.