Math-First Tax Calculations
Demystifying payroll math, federal withholdings, and state tax brackets with transparent, free, and accurate estimation tools.
Our Mission
At PayCheckup, we believe that understanding your paycheck shouldn't require a degree in accounting. Every pay period, millions of W-2 employees receive pay stubs with complex deductions—from FICA withholdings to local and state income taxes—without a clear understanding of the underlying math.
We built PayCheckup to serve as a fast, reliable, and completely free paycheck calculator that does the heavy lifting for you. Our goal is to provide transparent, direct, and math-first estimations, helping you plan your personal finances with absolute clarity.
How We Ensure Accuracy
Payroll compliance is built on precise guidelines. To provide reliable estimates, the mathematical engine powering PayCheckup is continuously updated and audited against:
- IRS Publication 15-T: Federal income tax withholding tables, incorporating both standard and graduated withholding calculations.
- Federal Insurance Contributions Act (FICA): Exact tax formulas representing the 6.2% Social Security rate (capped at the 2026 wage limit of $184,500) and the 1.45% Medicare rate (plus the 0.9% additional Medicare surcharge for high earners).
- State Departments of Revenue: Active tax brackets, standard deductions, and personal exemption rules for all 50 states plus the District of Columbia.
Core Calculator Features
Whether you are calculating a salaried compensation package or tracking hourly wages, PayCheckup offers tailored features:
State-by-State SIT
Accurate state income tax calculations matching progressive, flat, or zero-tax rules across the United States.
Pre-Tax Adjustments
Simulate how traditional 401(k), HSA, or medical premium deductions lower your overall taxable income.
FICA & Payroll Taxes
Separate calculations for Social Security, Medicare, and optional local/county payroll taxes where applicable.
Educational Walkthroughs
Every state paycheck page provides a line-by-line mathematical breakdown showing exactly how net pay is derived.
Have questions about our calculation engine or need to report a tax rule discrepancy? Contact our support team at support@paycheckup.org.