Marginal Tax Rate
Quick Definition
The tax rate applied to the last dollar of income earned, determined by the taxpayer's tax bracket.
Key Takeaways
- The marginal rate applies only to income within that bracket, not all income
- Your effective (average) tax rate is always lower than your marginal rate
- Use marginal rates to calculate the tax impact of additional income or deductions
- Tax-deferred contributions (401k, IRA) reduce taxes at your marginal rate
What Is Marginal Tax Rate?
The marginal tax rate is the percentage of tax applied to the next dollar of taxable income, which corresponds to the taxpayer's highest applicable tax bracket. The U.S. uses a progressive tax system with seven federal income tax brackets, where higher income levels are taxed at progressively higher rates. Crucially, the marginal rate only applies to income within that bracket, not all income — this is one of the most misunderstood concepts in personal finance. For example, moving into the 24% tax bracket does not mean all income is taxed at 24%; only the income above the 22% bracket threshold is taxed at the higher rate. Understanding marginal vs. effective (average) tax rates is essential for making informed financial decisions about additional income, deductions, and retirement contributions.
Marginal Tax Rate Example
- 1A single filer earning $100,000 in 2026 has a 24% marginal rate but an effective rate of approximately 17% because lower brackets tax income at 10%, 12%, and 22% first.
- 2Contributing $5,000 to a traditional 401(k) saves $1,200 in taxes if your marginal rate is 24%.
- 3A freelancer in the 32% bracket who earns an additional $10,000 pays $3,200 in federal tax on that income (plus self-employment tax).
Related Terms
Tax Bracket
An income range taxed at a specific rate within the progressive federal income tax system.
Standard Deduction
A fixed dollar amount that reduces taxable income for taxpayers who do not itemize deductions.
Itemized Deduction
Individual tax-deductible expenses that can be listed separately instead of taking the standard deduction.
Tax-Deferred
An investment or account where taxes on earnings are postponed until funds are withdrawn, typically in retirement.
FAFSA (Free Application for Federal Student Aid)
The federal form used to determine eligibility for financial aid including grants, loans, and work-study programs.
401(k)
An employer-sponsored retirement savings plan with tax advantages, often including employer matching contributions.
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