Product & methodology · Updated September 12, 2026
Know what goes into your after-tax estimate.
AfterTaxUS is a free educational income-planning tool. It helps you explore how tax treatment changes the income you might keep from investments, and how that income fits into a broader portfolio. It does not prepare or file tax returns, recommend trades or execute investments.
Three ways to explore your income
1. Compare two investments—no account needed
The investment comparison calculator applies one shared investment amount to two options. You set yields, tax treatments, filing status, state, background income and deduction assumptions. It compares estimated annual income, tax cost and after-tax yield.
The comparison estimates the extra federal and state tax attributable to each option against the background-income calculation. After-tax income is the option’s income minus that estimated tax difference; after-tax yield divides that amount by the investment amount. The result is sensitive to the income and deduction assumptions you enter.
Its background-income field is a simplified input, not a detailed breakdown of wages, Social Security or multiple income sources. Check the input help and deductions rather than assuming a number from a tax return maps directly to every field.
2. Estimate broad income—no login
The income calculator offers a different starting point: ordinary and investment income, filing status, deduction method, state and supported local tax settings. It requests estimates from the AfterTaxUS backend. It is an estimate of income under those settings, not a paycheck or full-return calculator.
3. Model the whole picture—a free account
The full portfolio app adds multiple accounts and income rows, asset tax treatments, replacement-investment what-ifs, comparison baselines, saved workbook versions, undo/redo and tax breakdowns. It also includes supported local-tax and W-2 payroll settings. A free account is required to save and return to a workbook.
When an account is excluded from after-tax income, its included income still contributes to the tax calculation. The app removes that income from the spendable-income display. This lets you explore income that increases the tax burden but is not available for spending.
What the results do—and don’t—cover
- Tax year and coverage: the current model is 2025. State selection does not mean every state rule, credit, exemption, surcharge, residency situation or deduction is modeled or independently validated.
- Quick comparison: excludes local and payroll taxes, credits, AMT, automatic state eligibility adjustments, partial-year residency and state-specific capital-gains taxes. State deductions may need your own adjustment.
- Full app: offers additional settings, but is not a complete tax-return calculation. Local coverage is a supported catalog, not every city, county or district. Correct income classification and tax-treatment settings are essential.
- Yields: catalog values are illustrative samples, not live quotes. Verify the issuer’s current distribution information. Distribution yield, SEC yield and total return are different measures; compare like with like.
- Investment outcomes: a higher estimated after-tax income is not a recommendation. The tools do not establish suitability or account for all fees, leverage, credit risk, liquidity or future price changes.
- Warnings: resolve unmapped tax treatments and other input warnings before relying on a result. Confirm important tax decisions with a qualified professional and current official guidance.
Why the tax treatment matters
Not all investment income is taxed the same way. Direct U.S. Treasury interest is subject to federal income tax but exempt from state and local income taxes. Some municipal-bond interest is exempt federally; that does not automatically make every fund distribution exempt in your state. See IRS Topic 403: Interest received.
Ordinary dividends and qualifying dividends can receive different federal treatment. Check the distribution’s classification, eligibility and holding-period requirements rather than relying on the symbol alone. See IRS Topic 404: Dividends and other corporate distributions.
These sources explain the concepts; linking them does not mean the IRS endorses AfterTaxUS or has validated its calculations.
Using AfterTaxUS with ChatGPT or Claude
You can discuss a calculator result or its assumptions with an AI assistant without connecting an account. Start with the tax year, state, filing status, income type and the question you want to explore. Avoid sharing identifying or financial information you do not want the assistant provider to receive.
The full app also provides an optional MCP connection for compatible clients. After signing in, the app’s menu includes a “Copy ChatGPT URL” control. Treat that connector URL as a secret: it grants access to your workbook. Connect it only through a client you trust and review the permissions and requested changes. ChatGPT and Claude features, account requirements and connector setup vary.
An assistant can use the actions its connected client exposes; a public web page does not grant it private workbook access. AfterTaxUS is not affiliated with or endorsed by OpenAI or Anthropic. AI-generated interpretations are not professional tax advice.
Your inputs and your choices
The standalone investment comparison calculates estimates in your browser. The income calculator and full app use AfterTaxUS backend services. Saved portfolio workbooks require an account. The public site also collects usage analytics; see the privacy policy before entering personal information.
No bank connection is needed to manually enter your numbers. AI access is optional. Links from the investment comparison to the full app do not automatically transfer the comparison inputs.