How Tax Brackets Actually Work (And Why Earning More Never Costs You Money)

Earning more money never leaves you with less after-tax income. This is a foundational fact about the U.S. tax system that a surprising number of people don't believe, because they misunderstand how brackets function. The fear is real and common: 'If I get a raise and move into the next bracket, I'll end up taking home less.' That cannot happen. The U.S. uses a marginal tax system, where each bracket rate applies only to the income within that bracket — not to your entire income.

In 2024, the federal brackets for a single filer are: 10% on the first $11,600, 12% on income from $11,601 to $47,150, 22% on $47,151 to $100,525, 24% on $100,526 to $191,950, 32% on $191,951 to $243,725, 35% on $243,726 to $609,350, and 37% above $609,350. A single filer with $60,000 in taxable income doesn't pay 22% on all $60,000 — they pay 10% on the first $11,600, 12% on the next $35,550, and 22% only on the final $12,850. The bracket describes the rate on the last dollar earned, not on every dollar.

Marginal rate vs. effective rate — the distinction that matters most

Your marginal rate is the rate that applies to your next dollar of income — useful for decisions about deductions, retirement contributions, and additional earnings. Your effective rate is your total tax bill divided by your total taxable income — the actual average rate you paid. For the $60,000 filer in the example above: their marginal rate is 22%, but their effective rate is roughly 13.5%. The effective rate is always lower than the marginal rate for any taxpayer with income spread across multiple brackets.

The marginal rate is what drives financial decisions. A $1,000 contribution to a traditional IRA saves you $220 in taxes if you're in the 22% bracket — $1,000 times your marginal rate. A $1,000 bonus adds $220 in federal income tax, not $1,000 times your effective rate. Understanding the marginal rate is what makes retirement contribution decisions, tax-loss harvesting, and income-shifting strategies tractable — you're always calculating the tax impact on the next dollar, not on all your dollars.

The standard deduction comes first — taxable income is not your gross income

The bracket rates apply to taxable income, not gross income. For 2024, the standard deduction is $14,600 for single filers and $29,200 for married filing jointly. A single filer earning $75,000 in W-2 wages has a taxable income of approximately $60,400 after the standard deduction — not $75,000. That $14,600 reduction moves the first $14,600 out of any bracket entirely: it's tax-free. Pre-tax retirement contributions (401k, IRA) reduce taxable income further. The brackets apply to what's left after these reductions.

A practical illustration: a married couple earning $120,000 combined, with $23,000 contributed to a 401k and the standard deduction applied, has taxable income of approximately $67,800. Their marginal rate is 12%. Every dollar of 401k contribution above that saves them 12 cents in federal taxes. If their income were $180,000 combined with the same deductions, taxable income would be around $127,800 — marginal rate of 22%. Same contribution, more tax savings per dollar deducted. The higher your marginal rate, the more valuable pre-tax deductions become.

FICA taxes — the part that doesn't follow bracket logic

Federal income tax isn't the only tax on your paycheck. FICA taxes — Social Security (6.2%) and Medicare (1.45%) — are flat rates applied to earned income regardless of bracket. Social Security tax applies to the first $168,600 of wages in 2024 (the wage base); above that, the 6.2% stops. Medicare has no cap and adds an additional 0.9% surcharge for income above $200,000 (single) or $250,000 (married). FICA taxes are why the effective tax rate on a moderate income often feels higher than the federal income tax bracket implies — you're paying an additional 7.65% before income tax brackets even enter the calculation.

State income taxes add another layer. Nine states have no income tax (Florida, Texas, Nevada, Washington, Wyoming, South Dakota, Alaska, New Hampshire on wages, Tennessee on wages). Most others impose rates ranging from flat 3% to 4% structures (Illinois, Pennsylvania) to progressive systems reaching 9% to 13.3% (California, Oregon, New Jersey). The combined federal, state, and FICA burden on a $120,000 income in California is materially different from the same income in Texas — a calculation worth running when comparing job offers across states.