In the U.S., there is no difference in the tax rate between overtime and regular pay. Both are subject to the same federal, state, and local income tax rates, as well as payroll taxes like Social Security and Medicare.
However, because overtime increases total earnings, it might push a person into a higher tax bracket, causing a higher portion of their income to be taxed at a higher rate. This doesn’t mean overtime itself is taxed differently—it just affects the total taxable income for the year.
So, while the tax rate doesn’t change specifically for overtime, your overall tax liability can increase due to the additional income.