The tax entry threshold is the income level at which a person begins paying federal income taxes. Unlike payroll taxes, income taxes do not start at the first dollar of earnings. Rather, the federal income tax system exempts an amount of income from taxation based on the type of tax unit (married or unmarried, with or without children) and the number of people in the tax unit. Tax credits can raise the tax entry threshold further. This article compares the tax entry threshold to the poverty line providing one way to judge how the tax system treats low-income families and providing a comparison of the relative generosity of the income tax for families with and without children.