While tax rules and policies may change, one thing that generally stays the same is that your income is taxed "progressively." That means as your income reaches higher tax brackets, your effective tax rate goes up as well. The federal tax rates are divided into seven brackets based on your filing status. There are five filing status options, depending on your situation and whether you're married or single.
The highest tax bracket your income falls into is known as your "marginal" tax rate. However, not all your income is taxed at the highest rate. Only the money you earn within a specific tax bracket is taxed at that rate.
Let's take a closer look at how progressive taxation works by imagining that you're single and earning $40,000 a year in taxable income. As shown in the chart below, for tax year 2025 you'd pay 10% in taxes on the first $11,925 of your income and 12% on the remaining $28,075. Your marginal tax rate would be 12%, because it's the highest tax bracket for your income.