People often quote their tax bracket as if it describes their whole tax bill, but the marginal rate only describes the tax on the top slice of income. Understanding this distinction is one of the most useful things you can do for financial planning — it changes how you think about raises, side income, retirement withdrawals, and even whether an extra hour of overtime is "worth it" after tax.
Marginal vs. Effective Rate
Your marginal rate is the rate on your last dollar earned. Your effective rate is your total tax bill divided by your total income — a blended average across every bracket you passed through. The effective rate is always lower than or equal to the marginal rate for anyone earning above the lowest bracket.
Worked Example
A single filer with $70,000 in taxable income sits in the 22% federal bracket — that's their marginal rate. But because the first ~$48,475 was taxed at only 10% and 12%, their actual tax bill comes to roughly $10,315, an effective rate of about 14.7% — nearly 7.3 percentage points below their marginal rate.
| Metric | Rate | What It Means |
|---|---|---|
| Marginal rate | 22% | Tax on the next dollar earned |
| Effective rate | ~14.7% | Blended rate on all $70,000 |
| $5,000 bonus at marginal rate | 22% | ~$3,900 kept after federal tax |
Why It Matters for Financial Decisions
If you're deciding whether to take on a freelance project, contribute to a traditional 401(k), or accept overtime, your marginal rate — not your effective rate — tells you the real after-tax value of that extra income. A pre-tax retirement contribution, for instance, saves you tax at your marginal rate, which is why it's often more valuable for higher earners in higher brackets.
Figures above are illustrative estimates only, not tax advice. Actual rates depend on filing status, deductions, credits, and state tax rules — consult a tax professional for precise figures.