Marginal vs Effective Tax Rate, Explained

Ask most people what happens when a raise pushes them into a higher tax bracket, and you’ll often hear the same worry: their whole paycheck suddenly gets taxed at the higher rate, so the raise isn’t really worth it. That’s a myth, and a costly one, since it’s talked people out of raises, bonuses, and side income for decades. The US federal income tax is progressive, meaning only the slice of your income that falls inside each bracket is taxed at that bracket’s rate. Understanding that difference, between your marginal rate and your effective rate, is the key to reading your own tax bill correctly.

The misconception, and the correct mental model

The misconception goes like this: if you’re “in the 22% bracket,” the IRS takes 22% of every dollar you earned. Under that logic, earning one extra dollar that bumps you into the next bracket could theoretically cost you more in tax than the dollar itself. It’s an intuitive way to misread a tax table, but it isn’t how the calculation works.

The correct model treats your income like water filling a series of buckets, one bracket at a time. The lowest bucket fills first, taxed at the lowest rate. Once it’s full, the next dollars spill into the next bucket, taxed at that bracket’s (higher) rate, and so on, until you run out of income. Your marginal rate is just the rate on the last, highest bucket your income reached. It only applies to the dollars in that bucket, not to every dollar you earned. Your effective rate is the average rate across all your income: total tax divided by taxable income. Because the lower buckets are always taxed at lower rates, your effective rate is always lower than your marginal rate, often by a wide margin.

This is also why an extra dollar of income can never cost you money overall. That dollar is taxed at your marginal rate, which is never more than 100%, so you always keep something from it. What changes as you cross into a new bracket is the rate on income above the threshold, not the rate on income you already earned below it.

The formula

Total Tax = sum, for each bracket from lowest to highest, of:
            (min(taxable income, bracket's upper bound) - bracket's lower bound) x bracket's rate,
            stopping once taxable income is fully accounted for

Marginal Rate  = rate of the bracket containing your last dollar of taxable income
Effective Rate = Total Tax / Taxable Income

Each bracket only contributes tax on the portion of your income that actually sits inside it. If your income doesn’t reach a bracket’s upper bound, that bracket only gets taxed up to your actual income, and every bracket above it contributes nothing.

Worked example: $60,400 taxable income, single filer

Using the 2024 federal brackets for a single filer, here’s how $60,400 of taxable income breaks down bucket by bucket:

• 10% bracket, $0 to $11,600: $11,600 taxed at 10% = $1,160.00
• 12% bracket, $11,600 to $47,150: $35,550 taxed at 12% = $4,266.00
• 22% bracket, $47,150 to $60,400: $13,250 taxed at 22% = $2,915.00

Add those three pieces together: $1,160.00 + $4,266.00 + $2,915.00 = $8,341.00 in total federal tax.

That $60,400 taxpayer lands in the 22% bracket, since their last dollar of income falls inside it, so their marginal rate is 22%. But notice that only $13,250 of their income was actually taxed at that rate. The rest was taxed at 10% and 12%. Divide total tax by taxable income and you get their true average tax rate: $8,341.00 / $60,400 = 13.81% effective rate, a full 8.19 percentage points below their marginal rate.

That gap is the whole point. If this taxpayer got a raise that pushed their taxable income to $65,000, only the additional $4,600 above $60,400 would be taxed at 22%, adding $1,012 in tax. Their earlier income keeps being taxed exactly as it was before. Nothing retroactively gets taxed at a higher rate.

A few nuances worth knowing

This bracket math applies to taxable income, meaning income after your standard or itemized deductions, not your gross salary. If you only know your gross pay, run it through an income tax calculator that applies the standard deduction first, since plugging gross income into a bracket calculator will overstate both your marginal and effective rates.

The brackets and thresholds shown here are for 2024 federal income tax and adjust for inflation most years, so don’t assume this year’s numbers carry over unchanged. They also apply only to ordinary income; long-term capital gains and qualified dividends are taxed under a separate, generally lower rate schedule. And this is federal tax only: state income tax, where it applies, is calculated separately, often with its own progressive brackets, and payroll taxes like Social Security and Medicare are calculated as flat percentages on top of this, not folded into your bracket math at all.

FAQ

If I get a raise, could I actually take home less money? No. Moving into a higher bracket only raises the rate on the income above that bracket’s threshold, not on income you already earned. A raise always increases your take-home pay, just by a bit less than the raise’s full amount once the higher marginal rate applies to that slice.

Why is my effective tax rate so much lower than the bracket I’m “in”? Because your effective rate averages in every lower bracket your income passed through on the way up, and those lower brackets are taxed at lower rates. Only the top slice of your income is taxed at your marginal rate; everything below it keeps the rate it was always taxed at.

Does this bracket math include state taxes or payroll taxes like Social Security? No. This covers federal income tax only. State income tax is calculated separately under its own bracket structure (or flat rate, depending on the state), and Social Security and Medicare are flat-percentage payroll taxes calculated independently of your income tax bracket.

Use the Tax Bracket Calculator to see your own bracket breakdown.