A common worry when someone is offered a raise is that it will "push them into a higher bracket" and leave them worse off. That cannot happen under a progressive bracket system, and the reason is worth being precise about, because the same confusion makes people badly misjudge what they actually pay.
Brackets apply to slices of income, not to the whole of it. The 2025 federal schedule for a single filer has seven rates, from 10 percent up to 37 percent, and each one applies only to the income falling inside its own band. Moving into a higher band changes the rate on the next dollar. It never changes the rate on the dollars below it.
Work it through on $90,000 of taxable income for a single filer. The top slice sits in the 22 percent bracket, so the marginal rate is 22 percent. But the total federal income tax computed across all seven bands is $14,714.00, which is an effective rate of 16.3 percent. The gap between 22 and 16.3 is not a rounding difference; it is the whole structure of the system. Every dollar below the top band was taxed at 10, 12 and 22 percent on its way up.
So a raise is always worth taking. Only the portion above the threshold is taxed at the higher rate, and the rest of your income is untouched.
Payroll tax works on a completely different principle and is where the intuition usually breaks. Social Security is 6.2 percent, but only up to a wage base of $176,100, above which it stops entirely. Medicare is 1.45 percent with no cap at all, plus an additional 0.9 percent above 200,000 single or 250,000 married. On the $90,000 above, employee-side FICA comes to $6,885.00, none of which is affected by which income tax bracket you are in.
That produces a genuinely counterintuitive result: Social Security is regressive at the top, because a high earner stops paying it partway through the year, while Medicare is not. It is also why "what tax bracket am I in" is close to useless as a description of what leaves your paycheck. Three separate schedules are running at once, on different bases, with different caps.
Figures above are the 2025 federal brackets and FICA parameters, verified for bracket continuity and against the published wage base. The tax amounts were computed here across the full bracket schedule rather than quoted. This is not advice, and it ignores deductions, credits and state tax, all of which move the real number.
A paycheck calculator that applies federal, FICA and state rules together is at statewage.com.