People often say “I'm in the 24% bracket” as if 24% of their income disappears to taxes. But there are two different rates worth knowing: your marginal rate and your effective rate. Confusing them leads to bad decisions about raises, deductions, and retirement contributions.
What the marginal rate means
Your marginal tax rate is the rate applied to your next (or last) dollar of taxable income — in other words, your top bracket. It matters most for decisions at the margin, such as whether an extra shift, a bonus, or a pre-tax 401(k) contribution is worth it. A deduction saves you tax at your marginal rate, so a $1,000 deduction for someone in the 24% bracket is worth $240. This is the number to use when weighing one more dollar of income or one more dollar of deduction.
What the effective rate means
Your effective tax rate is your total tax divided by your total income — the true average bite across all your dollars. Because the lower brackets tax your early dollars at 10% and 12%, the average is always below your marginal rate. The effective rate is the honest answer to “what percentage of my income goes to federal income tax?” It is the better number for budgeting and year-over-year comparisons.
Why the two diverge
In a progressive system, every taxpayer above the lowest bracket has an effective rate lower than their marginal rate. A single filer in the 24% bracket might have an effective rate closer to 14% or 15% once the lower layers and the standard deduction are counted. The gap widens as more of your income sits in higher brackets while your early dollars stay cheaply taxed. Only someone whose entire income fit in the 10% bracket would see the two rates match.
Which rate to use when
Use the marginal rate for forward-looking decisions: the value of a deduction, the tax on extra income, or the benefit of deferring income. Use the effective rate to understand your overall burden and to compare your situation across years or against averages. Mixing them up — for example, assuming a raise is taxed at your effective rate — leads to underestimating the tax on new income. Keep both numbers in mind and apply the right one to the right question.
A single filer with $100,000 of taxable income in 2025 sits in the 22% marginal bracket. But after the 10%, 12%, and 22% layers are combined, the total federal income tax works out to roughly $17,000, an effective rate near 17%. The 22% describes only the last dollars, while 17% describes the whole.
Key takeaways
- Marginal rate is the tax on your next dollar; effective rate is your average across all dollars.
- Deductions and extra income are valued at your marginal rate.
- Your effective rate is always lower than your marginal rate in a progressive system.
- Use effective rate to gauge your true tax burden, marginal rate for decisions at the margin.
Common mistakes
- Assuming your entire income is taxed at your top bracket rate.
- Valuing a deduction at your effective rate instead of your marginal rate.
- Comparing your marginal rate to someone else's effective rate.
FAQ
Which rate is higher?
Your marginal rate is higher than your effective rate for anyone earning above the lowest bracket, because early dollars are taxed at lower rates.
How do I calculate my effective rate?
Divide your total income tax by your income. Most tax software shows both your marginal bracket and your effective rate on the summary page.