Pre-Tax vs. Post-Tax Deductions: How They Impact Your Paycheck

Discover the difference between 401(k) pre-tax contributions and Roth post-tax contributions and how each affects your tax bill.

Understanding the Core Concept

When managing your personal finances or preparing for a new job offer, knowing how taxes impact your gross earnings is critical. Federal income taxes in the United States operate under a progressive tax structure, meaning higher portions of income are taxed at higher marginal rates.

Key Takeaways for 2026

• FICA Taxes: Social Security tax is 6.2% up to $184,500 in earnings for 2026, while Medicare tax is 1.45% on all earnings.
• Pre-tax Benefits: Participating in 401(k) retirement plans and Health Savings Accounts (HSAs) lowers your adjusted gross income (AGI) and reduces your taxable income.
• State Taxes: Nine U.S. states levy zero state income tax on salaries and hourly wages.

How to Use Our Free Paycheck Calculator

You can test different salary scenarios, hourly wage rates, 401(k) contribution percentages, and filing statuses using our free Paycheck Calculator.