Millage is a term that represents the tax rate levied on real estate or other property. A mill is one thousandth of a dollar, or one tenth of one cent. The millage rate is the number of dollars of tax assessed for each $1,000 of property value. A rate of 10 mills means that $10 in tax is levied on every $1,000 in assessed value. A school district typically will set the millage rate each spring as it calculates what it needs to fund its final budget.