2025 Tax Withholding: A Practical Guide to Your Paycheck

October 25, 2025 • Pocket Flow Team • 10 min read

Withholding is how your employer pre-pays your income taxes throughout the year. Pocket Flow’s demo uses the same federal and state logic as our full calculator, with one important limitation: it does not include pre‑tax deductions (like 401(k) or HSA) in the demo. The full app does.

What’s in your paycheck

• Federal income tax — calculated using IRS Publication 15‑T (2025), based on your filing status and pay frequency.
• FICA — Social Security (6.2% up to the annual wage base) and Medicare (1.45%, plus 0.9% additional for high earners).
• State taxes — varies by state; we cover all 50 states (and handle no‑tax states correctly).

Why estimates vary

Real paychecks include deductions, employer-specific settings, and sometimes local taxes. That’s why we present a quick estimate on the landing page, and deeper, configurable calculations inside the app.

Curious what would change if you increased 401(k) or adjusted your W‑4? That's exactly what Pocket Flow helps you explore.