Certified Property Values and Mill Levies

The “Certified Values” are total taxable property values determined by the Department of Revenue for each tax jurisdiction.

The department provides these values to the tax jurisdictions every year on the first Monday in August.

2021 Certified Values will be available on August 2, 2021.

The full details of the report, including the certified values of every tax jurisdiction and the statewide totals can be can be found at Property.MT.gov.

Local governments establish their budgets and set their mill levies for property tax calculation and collections based on the certified taxable value provided to each taxing jurisdiction.

Calculating Levies and Property Tax

To calculate the number of mills in each jurisdiction and property tax due, follow the steps below.

This procedure is outlined in 15-10-420, MCA.

Step 1

Calculate Adjusted Property Tax Revenue (APTR)

The current year’s adjusted property tax revenue is equal to the jurisdiction’s previous year’s property tax revenue increased by one-half of the average rate of inflation over the previous three years:

$\text{APTR} = \text{Previous Year's APTR} \times \left(1 + \left(\frac{\text{3 Years Inflation}}{2}\right)\right)$

Step 2

Calculate Maximum Mills

Next find the jurisdiction’s maximum mills.

This is 1,000 times the jurisdiction’s Adjusted Property Tax Revenue (APTR) divided by its Certified Taxable Value minus its Newly Taxable Value (Rounded down to the third decimal):

$\text{Maximum Mills} = 1,000 \times \left(\frac{\text{APTR}}{\text{Certified Taxable Value} - \text{Newly Taxable Value}}\right)$

Step 3

Calculate Millage Rates

Find the Millage Rate. This is the total number of mills from all jurisdictions for your property divided by 1,000.

$\text{Millage Rate} = \frac{\text{Total Mills}}{1,000}$

Step 4

Estimate Property Tax

Finally, property owners multiply the Taxable Value by the Millage Rate to find their Property Tax.

$\text{Property Tax} = \text{Taxable Value} \times \text{Millage Rate}$

This is an estimate of general property taxes. Local governments may also assess special fees and assessments. Property owners should contact their County Treasurer for more information on special assessments or fees.

Example Levies and Property Tax

For this example, we will look at a property with a $2,793 Taxable Value, in one tax jurisdiction with:

Previous Year’s Property Tax Revenue: $1,000,000
Three Year Inflation: 2%
Current Year Certified Taxable Value: $2,000,000
Newly Taxable Value: $100,000

We will also assume a second tax jurisdiction with 304 mills.

Step 1

Calculate Adjusted Property Tax Revenue (APTR)

$\text{APTR} = \$1,000,000 \times \left(1 + \left(\frac{0.02}{2}\right)\right)$
$\text{APTR} = \$1,000,000 \times 1.01$
$\text{APTR} = \$1,010,000$

Adjusted Property Tax Revenue: $1,010,000

Step 2

Calculate Maximum Mills

$\text{Maximum Mills} = 1,000 \times \left(\frac{\$1,010,000}{ (\$2,000,000 - \$100,000)}\right)$
$\text{Maximum Mills} = 1,000 \times \left(\frac{\$1,010,000}{\$1,900,000}\right)$
$\text{Maximum Mills} = 1,000 \times (0.531)$
$\text{Maximum Mills} = 531$