How to find your marginal tax rate
Start with your taxable income and find the tax bracket it falls in. A single filer with $70,000 of taxable income in 2026 is in the 22% bracket, which runs from $50,400 to $105,700, so each extra dollar of ordinary income costs 22 cents of federal income tax. That is the statutory marginal rate.
For the full picture, add the other taxes the same dollar triggers. State income tax usually applies on top. If the dollar is wages, the employee share of payroll tax adds 7.65% up to the 2026 Social Security wage base of $184,500 and 1.45% above it, plus 0.9% of Additional Medicare tax on wages over $200,000 for a single filer ($250,000 joint). So a worker taking a bonus in the 22% bracket could face 29.65% before any state tax.
The most reliable method is to work out your tax twice, once as it stands and once with $1,000 more income, then divide the difference by $1,000. That test catches every phase-out and surtax that a bracket table leaves out.
Why your real marginal rate can exceed your bracket
Rules that phase in or out with income add hidden percentage points. The combined result is often called the effective marginal tax rate, and the table below shows common 2026 examples for federal tax alone.
The Social Security tax torpedo is the best known: in the 85% phase-in range, each extra dollar makes 85 cents of benefits taxable. The $6,000 senior deduction shrinks by 6 cents for every dollar of MAGI above $75,000 ($150,000 joint) through 2028. The Child Tax Credit falls $50 for each $1,000 of MAGI above $200,000 ($400,000 joint). And investment income above the net investment income tax threshold adds 3.8%.
Some effects are cliffs rather than rates. One dollar over an IRMAA tier raises Medicare premiums by a fixed amount two years later, and crossing an income limit can cost an entire credit. A cliff is best measured in dollars, since spreading it over a single dollar produces a meaningless rate.
Marginal vs. effective tax rate
Your marginal rate describes the next dollar; your effective tax rate describes all your dollars together, total tax divided by income. The single filer above, with $70,000 of taxable income, owes $10,112 of federal income tax, an effective rate of 14.4% of taxable income, while the marginal rate is 22%.
Use the marginal rate for decisions at the edge: whether to take a bonus in December or January, how much a deduction saves, what a Roth conversion costs. A $1,000 deductible contribution in the 22% bracket saves $220, not 14.4% of $1,000. Use the effective rate to describe the overall burden and to compare years.
Mixing the two is a common error in both directions. People overestimate the tax on a raise by applying their top rate to all their pay, and underestimate the tax on a large IRA withdrawal by applying their average rate to it.
How marginal rates guide planning decisions
Most tax planning compares a marginal rate today with a marginal rate at some other time. The question is not what share of your income you pay overall, but what the specific dollars being moved will cost or save, and when. Because rates differ from year to year, the same dollar of income can cost 12 cents in one year and 32 cents in another, and moving it between those years is where most tax savings come from.
- Traditional or Roth: a pre-tax contribution saves your marginal rate today, while a Roth contribution avoids the rate the money would face when withdrawn.
- Roth conversions pay off when today’s rate on the converted dollars is lower than the expected rate on those dollars later.
- Timing income: shifting a bonus, gain or IRA withdrawal into a lower-rate year saves the difference between the two marginal rates.
- Deductions and charitable gifts are worth your marginal rate, but only if they actually reduce taxable income, for example because you itemize.
- In retirement, the marginal rate on each source helps decide which account to draw from next, the heart of a tax-efficient withdrawal strategy.
Illustrative numbers
A $10,000 Roth conversion by a single filer with $45,000 of taxable income
- Change in total tax
- Tax with the extra income minus tax without it, counting every tax, phase-out and surtax you want to include
- Change in income
- The extra amount tested, such as $1,000 of wages, an IRA withdrawal or a Roth conversion
When the extra amount crosses a bracket threshold, the result blends the two rates rather than matching either one.
Taxable income before the conversion$45,000 (12% bracket)
Room left in the 12% bracket, which ends at $50,400$5,400
Tax on the first $5,400 at 12%$648
Tax on the remaining $4,600 at 22%$1,012
Extra federal tax on the $10,000$1,660, or 16.6%
Marginal rate after the conversion22%
The conversion’s average cost is 16.6%, but its last dollars cost 22%. Converting only $5,400 would have kept every converted dollar at 12%, which is why conversions are often sized to the top of a bracket rather than to a round number.
At a glance
Federal marginal rate on $1 more of income in common 2026 situations
| Situation | What the next $1 triggers | Federal marginal rate |
|---|---|---|
| Ordinary income in the 22% bracket | 22 cents of income tax, nothing else | 22% |
| Wages in the 22% bracket, below the $184,500 wage base | Income tax plus 7.65% employee payroll tax | 29.65% |
| Social Security 85% phase-in, 12% bracket | $1.85 of taxable income | 22.2% |
| Senior deduction phase-out, 22% bracket, age 65+ | 6 cents of lost deduction | 23.32% |
| Child Tax Credit phase-out, 24% bracket | 5 cents of lost credit on average ($50 per $1,000) | About 29% |
| Ordinary income that pushes gains out of the 0% rate, 12% bracket | $1 of long-term gains moves from 0% to 15% | 27% |
| Investment income above the NIIT threshold, 24% bracket | 3.8% net investment income tax | 27.8% |
Put it in your plan
Marginal Rate in MoneyWhatIf
MoneyWhatIf’s Taxes page shows a selected year’s federal and state tax bills, each with the rate on the next dollar. Its tax map then adds extra ordinary income to that year in $1,000 steps up to $300,000 and plots the all-in marginal rate as a stepped line, counting the brackets, Social Security benefits pulled into tax, long-term gains pushed off the 0% rate and the net investment income tax. Cliffs, such as a Medicare surcharge tier, are marked separately in dollars. Payroll tax is left out, so a wage dollar would cost more than the line shows.
Common questions
Marginal Rate FAQs
How do you combine federal and state marginal tax rates?
Add the rates that apply to the next dollar: your federal bracket, your state’s rate at your income and any local income tax, plus 7.65% employee payroll tax if the dollar is wages below the $184,500 wage base. A worker in the 22% federal bracket, in a state that charges 5% at that income, keeps about 65 cents of a raise dollar after 34.65% in tax. If you itemize and stay under the 2026 SALT cap of $40,400 ($20,200 married filing separately), extra state tax is also deductible federally, which trims the combined rate slightly.
What is the highest marginal tax rate in 2026?
The top federal income tax rate is 37%, on taxable income above $640,600 for single filers and $768,700 for joint filers. Investment income at that level can also owe the 3.8% net investment income tax, for 40.8%. Top-bracket wages instead pay 1.45% Medicare tax plus 0.9% Additional Medicare tax, for 39.35%. State and local income taxes come on top of either figure.
Should I compare marginal or effective rates when choosing Roth or traditional?
Compare your marginal rate now with the rate the withdrawn dollars are likely to face later. A traditional contribution saves tax at today’s top rate, but in retirement the same dollars may fill several brackets, starting with income sheltered by the standard deduction. So the future rate often falls between your future effective and marginal rates. Holding both kinds of accounts, called tax diversification, hedges the guess.
What is the marginal tax rate on capital gains?
Long-term gains and qualified dividends face 0%, 15% or 20% in 2026, depending on total taxable income, plus the 3.8% net investment income tax above $200,000 of MAGI ($250,000 joint). Short-term gains are taxed at ordinary bracket rates. Because gains raise AGI, a gain can also make more Social Security taxable or shrink the senior deduction, so its true marginal cost can exceed its headline rate.