Our Methodology

How we ensure every calculation is accurate, up-to-date, and trustworthy.

Data Sources

All our calculations are based on official, publicly available data from authoritative sources:

Federal Tax Brackets: IRS Publication 15 (Circular E) and annual tax tables
FICA Rates: Social Security Administration guidelines (6.2% + 1.45% Medicare)
State Income Tax: Individual state department of revenue publications and tax schedules
State-Specific Rules: Exemptions, deductions, and special provisions per state law

Calculation Approach

1. Paycheck & Tax Calculators

For salary and paycheck calculations, we apply the following methodology:

• Calculate gross pay based on frequency (biweekly, monthly, etc.)
• Apply pre-tax deductions (401k, HSA, etc.)
• Compute federal withholding using IRS W-4 assumptions and tax brackets
• Calculate FICA (Social Security + Medicare) at statutory rates
• Apply state income tax based on state-specific brackets and rules
• Output net (take-home) pay

2. Salary Conversion Tools

Our salary-to-hourly and hourly-to-salary calculators use standard full-time work assumptions (40 hours/week, 52 weeks/year) while allowing customization for part-time or contract scenarios.

3. Specialized Calculators

Tools like overtime, bonus tax, and 401(k) impact calculators follow IRS and Department of Labor guidelines:

• Overtime: 1.5x or 2x regular rate (per FLSA standards)
• Bonus Tax: Supplemental wage withholding (22% flat or aggregate method)
• 401(k): Pre-tax contribution impact on taxable income

Updates & Maintenance

Tax laws and regulations change. Here's how we stay current:

Annual

Full review of federal tax brackets, FICA limits, and standard deductions (typically in November-December for the following year)

Quarterly

State tax law monitoring and updates for states with legislative changes

As Needed

Emergency updates for mid-year tax law changes or corrections

Limitations & Disclaimers

While we strive for maximum accuracy, our calculators have inherent limitations:

Calculators use standard withholding assumptions (single filer, no additional withholding) unless customized
State and local tax rules can be complex; we model the most common scenarios
Results are estimates your actual paycheck may vary based on employer-specific deductions, union dues, etc.
We do not provide tax filing advice or handle complex scenarios like multi-state income

How to Verify Our Calculations

Transparency is key. You can verify our calculations by:

Comparing results to your actual paycheck stub
Using IRS withholding calculators for federal tax cross-reference
Consulting your state's department of revenue tax calculator
Reviewing the formulas and explanations provided on each calculator page

Questions About Our Methodology?

We're committed to transparency. If you have questions about how a specific calculator works or notice an issue, we want to hear from you.