Payroll learning center
U.S. Payroll Tax Guides
Understand what appears on a paycheck, why withholding changes, and which official sources govern the calculation. Each guide connects the tax rule to a practical paycheck decision.
How Paychecks Are Calculated in the U.S.
Follow gross earnings through taxable wages, payroll taxes, deductions, and net pay.
Read guide →Form W-4 Explained
Understand filing status, multiple jobs, dependents, deductions, and extra withholding.
Read guide →Federal vs. State Taxes
Learn why federal, state, local, and FICA paycheck taxes must be separated.
Read guide →FICA Tax Guide
Understand employee Social Security and Medicare payroll taxes.
Read guide →Social Security Wage Base
See how the annual wage limit affects year-to-date Social Security withholding.
Read guide →Medicare Tax Guide
Learn regular and Additional Medicare withholding rules.
Read guide →Payroll Tax Calendar
Know when to review pay stubs, withholding, benefits, and annual tax forms.
Read guide →How these guides are reviewed
We prioritize IRS, Social Security Administration, Department of Labor, and state revenue-agency material. Calculator assumptions are labeled, sources are linked, and material tax-year changes are reviewed before figures are updated.