About AfterTaxMath & our tax methodology

AfterTaxMath is an independent, deterministic US paycheck and state tax arbitrage engine. We do not prepare tax returns, collect personal financial data, or sell leads. Every figure across our 1,350+ tables is computed directly from statutory formulas.

1. Federal income tax & standard deduction (2026)

We subtract pre-tax retirement deferrals (such as traditional 401(k) contributions up to the IRS elective deferral cap of $23,500) and the 2026 Federal Standard Deduction ($15,000 Single, $30,000 Married Filing Jointly, $22,500 Head of Household) from gross annual wages. The resulting Federal Taxable Income is passed through the seven IRS progressive brackets (10%, 12%, 22%, 24%, 32%, 35%, and 37%).

2. FICA payroll taxes (Social Security & Medicare)

Employee FICA taxes apply to gross W-2 wages before traditional 401(k) deductions:

• Social Security (OASDI): 6.2% on wages up to the annual taxable maximum of $176,100 (maximum employee withholding of $10,918).
• Medicare (HI): 1.45% on all wages with no cap, plus the 0.9% Additional Medicare Tax on wages above $200,000 ($250,000 for married couples filing jointly).

3. 50-State & Washington, D.C. income tax profiles

Each state is modeled according to its statutory structure: (a) 9 zero-income-tax states (AK, FL, NV, NH, SD, TN, TX, WA, WY) with 0% tax on W-2 salaries, (b) 14 flat-tax states (including AZ, CO, GA, IL, IN, IA, KY, LA, MI, MS, NC, PA, UT), and (c) 28 progressive-bracket jurisdictions (including CA, NY, NJ, OR, MN, HI, MA, and D.C.) with state-specific standard deductions and marginal brackets.

4. Relocation arbitrage & compounding

Relocation comparisons compute the net annual take-home difference between two states at the same gross salary and project the future value of investing that annual tax difference at a 7.0% annualized return over 5 and 10 years: FV = Δ × ((1 + r)ⁿ − 1) ÷ r.

Disclaimer & contact

All outputs are educational planning estimates and do not constitute tax, legal, or CPA advice. Local municipal wage taxes (such as New York City, Yonkers, Philadelphia, or county-level taxes in MD/IN/OH), itemized deductions, and dependent credits are not included in baseline tables. Spotted an issue? Contact us. Last reviewed 2026-10-18.