How this instrument works
This instrument isolates a single, well-documented piece of the tax plan Joe Biden campaigned on in 2020: letting the top marginal rate on ordinary income snap back from 37% to 39.6% for earnings above $400,000. Only the dollars above that line are taxed at the higher rate — the first $400,000 stays exactly as taxed today — so the tool multiplies the excess by 2.6 percentage points, the gap between the current top bracket and the pre-2018 one it would have restored.
The proposal never became law. The Inflation Reduction Act of 2022, the major tax bill that did pass, left ordinary income brackets untouched and instead added a corporate minimum tax and a stock buyback excise. What is modeled here is a historical what-if, useful to a policy analyst sanity-checking a talking point, a journalist fact-checking a claim about 'the Biden tax plan,' or a household well above the threshold curious what a single bracket change alone would have cost.
The 2020 platform also proposed payroll tax on wages above $400,000, taxing capital gains as ordinary income above $1 million, and capping itemized deductions — none of that is here. Combining this figure with other provisions and calling it 'the total Biden tax increase' overstates or understates the real proposal depending on which pieces you assume; this sheet answers one narrow question only.
- Enter your yearly figure in Taxable income, $ — this is income after deductions, not gross wages.
- Watch Additional tax under the proposal update as you type; it stays $0 for any figure at or below $400,000.
- Raise the figure past $400,000 to see the extra tax grow — the readout is 2.6% of whatever sits above the threshold.
- Compare two incomes by re-entering the field twice; the difference in the readout isolates what crossing further above the line costs under this one provision.
Worked example — $500,000 of taxable income
Set Taxable income, $ to 500000. The first $400,000 is untouched — it is taxed under the ordinary schedule already in force, and this instrument has no opinion on that part. Only the remaining $100,000 ($500,000 minus the $400,000 threshold) is exposed to the extra 2.6 percentage points this provision would have added to the top bracket.
$100,000 multiplied by 0.026 gives $2,600 — the figure the readout shows. That $2,600 is not a full tax bill and not even a full estimate of everything the 2020 plan touched; it is exactly and only what restoring the top marginal rate on ordinary income would have added for someone at this income level, holding every other rule fixed.
Questions
Why does the tax only apply above $400,000, not to the whole income?
Marginal brackets tax income in slices, not as a whole. Under this proposal, the first $400,000 keeps its existing tax treatment; only the portion earned above that line would face the higher 39.6% top rate instead of 37%, which is why the formula subtracts the threshold before multiplying by the 2.6-point gap.
Did this tax increase actually take effect?
No. This models a plank of the 2020 campaign platform, not enacted law. The Inflation Reduction Act of 2022 — the tax legislation that did pass — left the top ordinary income bracket at 37% and pursued revenue through a corporate minimum tax and other mechanisms instead.
Is $400,000 gross salary or taxable income?
Taxable income — pay, business profit, and other income after allowable deductions and adjustments, the figure that sits near the bottom of a tax return before the bracket schedule is applied. Gross salary is typically higher than taxable income, so a $400,000 salary usually produces a taxable income figure below the threshold.
Why is my number different from other 'Biden tax plan' estimates I've seen?
Most published estimates combine several 2020 proposals at once — this rate restoration plus payroll tax on wages above $400,000, capital gains taxed as ordinary income above $1 million, and capped itemized deductions. This instrument isolates only the marginal-rate change, so it will read lower than any estimate bundling the rest.
Does this account for the Alternative Minimum Tax or state taxes?
No. The formula covers one federal ordinary-income bracket change in isolation. AMT, state and local income tax, the Net Investment Income Tax, and payroll taxes all sit outside this calculation and would change the total owed independently of the figure shown here.
What does a negative or zero result mean?
The readout floors at $0 by design — the max(0, ...) term in the formula prevents any income at or below $400,000 from producing a negative adjustment, since the provision was never proposed to lower tax on income below the threshold.
References
- IRS — Federal income tax rates and brackets
- Tax Foundation — Details and Analysis of Biden's Tax Proposals
Read this first: This instrument shows arithmetic, not advice. Real offers add fees, taxes and terms that vary by lender and place — verify the figures against your actual paperwork before deciding anything.