How do tax brackets work?

The IRS has released the following tax brackets for the 2025 Tax Year - 

The United States operates under a progressive tax regime, which means different levels of your income get taxed at different rates. As an example, for a single filer with taxable income of $48,000, the first $11,925 will be taxed at 10%, while the remainder of the compensation will be taxed at 12%. Since the cap on the 12% threshold is $48,475, that will be the highest tax bracket this individual is subject to.  

Familiarity with these brackets helps individuals get a reasonable understanding of their effective tax rate, which is the percentage of tax an individual ultimately pays the IRS.