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    Tax / Federal

    Tax Return Analyzer (1040)

    Build a 2026 Form 1040 from the five lines that move the answer: ordinary income, capital gains, adjustments, deductions and credits. The output is the bracket-by-bracket tax, the effective and marginal rates, and what the return actually costs.

    FilingMFJCredits$0.00Gains$10,000 at LTCG rates
    Total federal tax
    $10,415
    7.89% of AGI
    AGI
    $132,000
    Deduction $32,200
    Taxable income
    $99,800
    After the deduction
    Marginal rate
    12.00%
    On the next dollar of ordinary income
    Tax by bracket
    Ordinary income only; long-term gains are stacked on top.
    Tax by bracket
    RateIncome in bracketTax
    10%$24,800$2,480
    12%$65,000$7,800

    Ordinary tax $10,280 · capital-gains tax $135.00 · NIIT $0.00.

    Inspect the model
    Choose a quick result view, a scaled comparison, or the complete diagnostic set.
    Federal tax against ordinary income
    The kinks are bracket changes; the slope is the marginal rate.
    Federal tax against ordinary income0.0001.646e+43.291e+44.937e+46.583e+48.228e+4$0.00$0.00$50,000$50,000$100,000$100,000$150,000$150,000$200,000$200,000$250,000$250,000$300,000$300,000$350,000$350,000$400,000$400,000Federal tax
    Canonical equations
    The exact relationships implemented by this engine.

    gross income − above-the-line adjustments · Form 1040 line 11.

    AGI − max(standard, itemised) · Line 15.

    ordinary brackets + LTCG rates + NIIT · Gains stack last.

    finance methodology

    A clear path from inputs to results.

    Build a 2026 Form 1040 from the five lines that move the answer: ordinary income, capital gains, adjustments, deductions and credits. The output is the bracket-by-bracket tax, the effective and marginal rates, and what the return actually costs.

    Step-by-step methodWorked exampleAssumptions explained

    How to use

    1. Set filing status.
    2. Set wages, salaries, tips.
    3. Set taxable interest.
    4. Set business / other ordinary income.
    5. Read the headline metrics, then check the table for the detail.

    The formula

    T=∑i(Biri)+TLTCG+TNIIT−CT = \sum_i (B_i r_i) + T_{LTCG} + T_{NIIT} - C

    Reference: IRS Rev. Proc. 2025-32 (2026 brackets and standard deduction).

    Worked example

    At the default inputs

    Inputs
    • Filing status: mfj; Wages, salaries, tips: 120000; Taxable interest: 2000; Business / other ordinary income: 0; Long-term gains and qualified dividends: 10000; Above-the-line adjustments: 0; Itemised deductions: 0; Non-refundable credits: 0
    Calculation path
    1. 1

      Build AGI → $132,000 Deduct → $99,800 Apply credits → $10,415

    Result

    Total federal tax: $10,415 · AGI: $132,000 · Taxable income: $99,800

    Interpreting the result

    A MFJ return with $132,000 of AGI owes $10,415 of federal tax — 7.89% effective and 12.00% marginal.

    Assumptions & limitations

    • Federal only; state tax is a separate calculator.
    • Long-term gains and qualified dividends are taxed at LTCG rates.
    • Credits are non-refundable and applied after tax.

    Frequently asked questions

    Does it file a return?

    No. It reproduces the arithmetic of the 1040.

    Why is the marginal rate not my bracket?

    Gains stack on top of ordinary income; the marginal rate is on ordinary income.

    Methodology last reviewed 2026-10-23. Results are informational and not financial or engineering advice — see our disclaimer.