What is Marginal Tax Rate?
Your marginal tax rate is the rate charged on your next dollar of income — the bracket your last dollar lands in. It's the number that matters for decisions, not your average rate.
How it works
Because the system is progressive, each additional dollar you earn is taxed at your top bracket's rate until it fills that bracket and spills into the next. That's why the marginal rate drives choices like whether to defer a bonus or make a bigger pre-tax retirement contribution.
A quick example
What people get wrong
Add your state's marginal rate to the federal one to see your true "next-dollar" rate. In a state like California, a high earner's combined marginal rate can top 45%.