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Marginal tax rate

A marginal tax rate is the tax rate that applies to an additional dollar of taxable income.

by Lee Schmidt

Published November 3, 2026

US federal income tax on ordinary taxable income is calculated in layers, with a different rate for each bracket. Entering a higher bracket does not make all your income taxable at that bracket's rate. Your marginal bracket rate describes the tax on your next dollar of ordinary taxable income, not the average tax on everything you earn.

In a sentence

  • "In this example, my marginal tax rate is 30%, but only the $1,000 above the cutoff falls in that bracket."
  • "My marginal tax rate applies to the next taxable dollar, while my effective tax rate describes an average."
  • "I check my marginal tax rate when estimating a raise, but I also account for payroll deductions."

How it's calculated

Finding your federal ordinary-income bracket rate starts with the income subject to that bracket schedule, not the amount deposited in checking.

  1. Use the bracket schedule for your filing status and the tax year you are calculating.
  2. Start with ordinary taxable income, not gross income. Taxable income reflects applicable adjustments and deductions; the entire salary is not automatically the amount to put through the brackets.
  3. Apply each bracket's rate only to the income within that bracket. Add those amounts to calculate the tax under the schedule.
  4. Identify the rate that applies to the next dollar. If an increase crosses a bracket boundary, split the increase between the applicable rates.

Additional bracket tax = sum of (extra taxable income in each bracket × that bracket's rate)

This calculation isolates the bracket mechanism. Credits, other taxes, and income-specific rules can change the full tax result.

An example

Suppose an illustrative tax system charges 10% on the first $20,000 of taxable income, 20% on the next $20,000, and 30% above $40,000. These are teaching assumptions, not current US federal brackets. Compare $39,000 with $41,000 of ordinary taxable income, with no credits or other taxes included.

Taxable income layerTax on $39,000Tax on $41,000
First $20,000 at 10%$2,000$2,000
Next $20,000 at 20%$3,800$4,000
Above $40,000 at 30%$0$300
Total bracket tax$5,800$6,300
Marginal tax rate20%30%

The extra $2,000 produces $500 of additional tax, consisting of $200 on the first $1,000 and $300 on the second. The earlier $39,000 keeps the same tax treatment rather than being recalculated at 30%.

Why it matters

A marginal tax rate helps you estimate the income-tax effect of earning another dollar, but it is not a complete paycheck calculator. A raise increases gross pay, while benefit deductions, retirement contributions, and income and payroll taxes help determine the change in take-home pay. Multiplying the whole raise by one bracket rate can miss both a bracket crossing and deductions that change taxable income.

A pretax retirement balance also is not an immediate tax bill. Estimating future withdrawal taxes requires assumptions about withdrawal timing, other income, and applicable rules. Applying today's marginal rate to the entire balance treats those assumptions as settled when they are not.

Marginal tax rate versus effective tax rate

A marginal tax rate applies to an additional dollar, while an effective tax rate is total tax divided by a stated income measure. The marginal rate helps evaluate a change; the effective rate describes the average burden for the income included.

In the example, $6,300 divided by $41,000 of taxable income gives an effective rate of about 15.4%, despite a 30% marginal rate. Other comparisons use gross or adjusted gross income as the denominator, so check which income measure and which taxes a quoted effective rate includes.

Common questions

Can moving into a higher bracket make me keep less income? Not because of the bracket change alone. The higher rate applies only to income above its cutoff, not to earlier income. Credits and benefit eligibility rules can affect the overall result, so a bracket calculation alone does not settle every case.

Is my marginal tax rate the same as paycheck withholding? No. Tax withholding is money sent toward your eventual tax liability as you are paid. Payroll calculations and the information you provide on withholding forms determine that amount; a larger withholding deduction does not mean all your pay is taxed at a higher bracket rate.

Does the same marginal rate apply to every kind of income? Not necessarily. Qualified dividends and many long-term capital gains can use separate federal rate schedules, while state income taxes and payroll taxes are separate calculations. An ordinary-income bracket rate is not an all-in rate for every additional dollar you receive.

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