Your marginal tax rate is the percentage you pay on your next dollar of income, not on all your income

The U.S. tax system uses tax brackets. You do not pay one rate on everything you earn. Instead, your income is taxed in layers: the first portion at one rate, the next portion at a higher rate, and so on. Your marginal tax rate is the rate applied to that topmost layer — the income you earn right now.

This matters because when you make a decision about earning more money, saving in a retirement account, or timing a bonus, you are really asking: what will this cost me in taxes? The answer is your marginal rate, not your average rate. A bonus that pushes you into the next bracket costs more per dollar than a bonus that stays within your current bracket.

For 2024, the federal brackets for single filers run from 10% up to 37%. The exact bracket you land in depends on your total income for the year. Your state may add its own tax on top.

Key Takeaways

  • Your marginal rate is the tax rate on your last dollar earned, which is what matters when you decide whether to earn more or contribute to a retirement account.
  • Your effective rate (total tax divided by total income) is always lower than your marginal rate because lower brackets explore to your first dollars.
  • Knowing your marginal rate helps you decide whether tax-loss harvesting, bunching deductions, or deferring income makes financial sense.
  • Your marginal bracket can shift during the year if you earn a bonus, receive a large capital gain, or add a spouse's income.
  • State and local taxes, Social Security tax, and Medicare tax all have their own brackets and can push your true marginal cost higher than the federal bracket alone.

How tax brackets actually work with an example

Suppose you are a single filer in 2024 and earn $50,000. The first $11,600 is taxed at 10%. The next portion, from $11,601 to $47,150, is taxed at 12%. The remaining $2,850 (from $47,151 to $50,000) is taxed at 22%. You do not pay 22% on all $50,000.

Your total federal tax is roughly $5,500. Divide that by $50,000 and your effective rate is about 11%. But your marginal rate — the rate on your next dollar — is 22%. If you earn one more dollar, it gets taxed at 22%, not 11%.

This is why marginal rate matters for decisions. If your employer offers you a $5,000 bonus, you do not keep $4,450 of it (89% of $5,000). You keep roughly $3,900 of it, because the bonus is taxed at your marginal rate of 22%, not your effective rate of 11%.

When your marginal rate changes during the year

Your marginal bracket is not fixed. It shifts whenever your income changes. A mid-year bonus, a large capital gain from selling stock, or a spouse's income can all push you into a higher bracket.

This is where tax planning becomes useful. If you know a bonus is coming in December, you might accelerate a charitable donation or a traditional IRA contribution before the bonus arrives. That deduction reduces your taxable income and keeps you in a lower bracket. The same deduction taken after the bonus might save you less in taxes because it would be applied against income taxed at a higher rate.

Similarly, if you are close to the edge of a bracket and considering selling an investment at a gain, you might wait until January to spread the gain across two tax years. This keeps more of the gain in a lower bracket.

Marginal rate versus effective rate: why the difference matters

Your effective rate is what you actually paid in total tax as a percentage of total income. It is useful for understanding your overall tax burden. But it is not useful for making decisions about the next dollar you earn or the next deduction you take.

Suppose you earn $75,000 and your federal tax is $8,500. Your effective rate is about 11.3%. But your marginal rate is 22% (the bracket for income between $47,151 and $100,525 for single filers in 2024). If you are deciding whether to take a consulting job that pays $2,000, you should expect to keep roughly $1,560 of it after federal tax, because the $2,000 is taxed at 22%, not 11.3%.

Many people confuse these two rates and end up surprised by how much of a raise or bonus goes to taxes. Using your marginal rate — not your effective rate — gives you the right number for any forward-looking decision.

How to find your marginal bracket

The IRS publishes tax brackets each year. For 2024, you can find them on IRS.gov under "Tax Brackets and Rates." The brackets change annually for inflation.

To find your bracket, add up your expected income for the year (wages, self-employment income, capital gains, and other taxable income). Then find the bracket that range falls into. That is your marginal bracket.

If you are married filing jointly, use the joint brackets. If you are single, use the single brackets. If you are self-employed, remember that you also owe self-employment tax (Social Security and Medicare), which adds roughly 15.3% on top of your federal income tax marginal rate for income up to the Social Security wage base.

State and local taxes add to your marginal rate

Federal brackets are only part of the picture. Most states have their own income tax with their own brackets. Some cities do too. These stack on top of your federal marginal rate.

If you live in California and are in the 24% federal bracket, California's top rate is 13.3%, so your combined marginal rate is 37.3% before you even consider self-employment tax or Medicare surtax. If you live in a state with no income tax, your marginal rate is just the federal rate plus any self-employment tax.

When you are deciding whether a financial move makes sense, use your true marginal rate: federal plus state plus local plus any self-employment or surtax that applies to you. A tax professional can calculate this for you if your situation is complex.

Using marginal rate to decide on retirement contributions and deductions

Knowing your marginal rate tells you how much a deduction or retirement contribution actually saves you. If you are in the 24% federal bracket and your state has a 5% income tax, a $1,000 contribution to a traditional IRA saves you $290 in taxes ($1,000 × 0.29). A $1,000 charitable donation saves you the same amount.

This is why bunching deductions can make sense. If you are close to the standard deduction threshold, you might donate $2,000 in one year instead of $1,000 each year. The bunched donation gets you over the threshold and saves you taxes at your marginal rate. The next year, you take the standard deduction. Over two years, you save more in taxes than if you spread the donations evenly.

The same logic applies to timing capital gains, taking required minimum distributions, or recognizing income from a side business. The question is always: at what marginal rate will this income be taxed? If you can shift income to a year when your marginal rate is lower, you save money.

Frequently Asked Questions

Is my marginal rate the same as my tax bracket?

Yes. Your marginal rate is the percentage associated with the tax bracket your income falls into. If your income lands in the 22% bracket, your marginal rate is 22%. The bracket is the range of income; the rate is the percentage applied to that range.

Why do people say I will lose money if I earn more?

They are confusing marginal rate with effective rate. Earning more always leaves you with more money after tax, because only the additional income is taxed at your marginal rate. If you earn a $10,000 bonus and your marginal rate is 32%, you keep $6,800. You do not lose money overall.

Does my marginal rate change if I get married?

Yes. If you marry and file jointly, your combined income may land in a different bracket than your individual income did. The joint brackets are wider, so you might stay in the same rate or move to a different one depending on your spouse's income. This is why some couples experience "marriage penalty" or "marriage bonus" in their taxes.

How do capital gains affect my marginal rate?

Long-term capital gains are taxed in their own brackets, which are lower than ordinary income brackets (0%, 15%, or 20% federally). But they are stacked on top of your ordinary income. If you have $50,000 in wages and $20,000 in long-term gains, the gains are taxed starting where your wage income ends, which may push you into a higher capital gains bracket.

Should I use my marginal rate or effective rate to plan taxes?

Use your marginal rate for any decision about earning more, contributing to retirement, or timing deductions. Use your effective rate to understand your overall tax burden. They answer different questions.