Property tax math: millage and exemptions

Turn mills into dollars

Property tax math starts with the taxable value for the particular levy. Assessed value is the value before applicable exemptions; taxable value is the remaining amount subject to that levy. Use the assessed value given in the problem rather than substituting the purchase price. An exemption reduces the taxable base, not the tax bill dollar for dollar.

A mill is one-tenth of a cent, or one-thousandth of a dollar. One mill produces one dollar of tax per thousand dollars of taxable value. Divide mills by 1,000 to obtain a decimal rate: 18 mills ÷ 1,000 = 0.018, which is 1.8 percent.

Calculate in order

Suppose a problem gives an assessed value of $300,000, an applicable exemption of $40,000, and a rate of 18 mills. First subtract: $300,000 − $40,000 = $260,000 taxable value. Then convert: 18 ÷ 1,000 = 0.018. Finally multiply: $260,000 × 0.018 = $4,680 annual ad valorem tax. Equivalently, $260,000 ÷ 1,000 = 260 thousand-dollar units, and 260 × $18 = $4,680. The exemption saves $40,000 × 0.018 = $720.

Three boxes show a calculation using given example amounts. Subtract a forty thousand dollar exemption from a three hundred thousand dollar assessment to obtain two hundred sixty thousand dollars taxable value. Divide eighteen mills by one thousand to obtain zero point zero one eight. Multiply the taxable value by that rate to obtain four thousand six hundred eighty dollars in annual tax. — Subtract, convert, then multiply.

Match each exemption to its levy

For Florida problems, use the exemption amount and levy eligibility stated in the question; the example figures here are assumptions, not statutory exemption amounts. If all levies use the same taxable value, add their millage rates before multiplying. If exemptions differ, calculate each levy separately and add the resulting taxes.

For example, assume a $300,000 assessment, a $25,000 exemption for a 6-mill school levy, and a $50,000 exemption for a 12-mill nonschool levy. School taxable value is $300,000 − $25,000 = $275,000; 6 ÷ 1,000 = 0.006; tax is $275,000 × 0.006 = $1,650. Nonschool taxable value is $300,000 − $50,000 = $250,000; 12 ÷ 1,000 = 0.012; tax is $250,000 × 0.012 = $3,000. Total tax is $1,650 + $3,000 = $4,650.

Florida's historic-property exemption illustrates why scope matters. Under section 196.1997, a qualifying local ordinance can exempt up to 100 percent of assessed value attributable to qualifying improvements. It does not exempt the entire property merely because it is historic. The exemption applies to the granting government's taxes, with statutory exclusions for bond-payment and specified voter-authorized taxes.

Check the result

A non-ad valorem charge supplied separately is added after the value-based tax calculation. To work backward, divide tax by taxable value and multiply by 1,000 to find mills. Divide tax by the decimal millage rate to find taxable value. Keep full precision during calculation and round the final dollar result to cents.