Two Basic Parts f ax Structure Tax Base The amount to which the tax rate is applied to determine tax due. For example, an individuals tax base for the federal income is his or her taxable income tax base for property tax is generally the fair market value of property subject to tax. Tax Rate Is merely the percentage rate applied to the tax baseTwo Basic Parts Of Tax Structure • Tax Base – The amount to which the tax rate is applied to determine tax due. • For example, an individual’s tax base for the federal income is his or her taxable income. • tax base for property tax is generally the fair market value of property subject to tax. • Tax Rate – Is merely the percentage rate applied to the tax base