Boulder County offices and walk-in services will be closed Monday, Jan. 20 for Martin Luther King Jr. Day

Property Tax Calculation

How Property Taxes Are Calculated

How Assessed Values Are Determined

Assessed property values are calculated by multiplying the actual value by 7.15% for residential property and by 29% for non-residential property. Each odd numbered year the residential assessment percentage is subject to change by the Colorado Legislature, as prescribed by the Gallagher amendment. The change in percentage maintains the present balance of the tax burden between residential and all other taxpayers.

Local Government Budget Process

Each year county commissioners, city councils, school boards, and special districts hold budget hearings to determine how many dollars will be needed for the following year’s operations. These hearings are usually held in September or October but may be held earlier. Check your local newspaper for the hearing dates. (See Budget & Finance for more information.)

Calculating the Assessment Rate/Mill Levy

The Tax Rate and Mill Levy are two different methods of expressing the same information:

  • The Tax Rate is expressed as a percentage
  • Mill Levy is expressed in mills (1 mill = $1 of property tax for every $1,000 of assessed value)

Each taxing entity determines what revenues will be required to operate the entity during the coming fiscal year. The required revenues are then divided by the total assessed value to determine the tax rate/mill levy per entity.

Generally, properties are affected by several taxing entities. To determine the Total Tax Rate, sum the tax rates for each entity that impacts the property.


  • The total assessed value for the county is determined by the assessor for $100,000,000.
  • The county commissioners determine the budgeted property tax revenues to be $1,398,000.
  • $1,398,000 (tax revenue) divided by $100,000,000 (assessed value) = 1.3980% (Tax Rate) or 13.98 Mills (Mill Levy)
  • Therefore the county tax rate is $13.98 in revenue for each $1,000 of assessed value

Calculating Property Taxes

Taxes are calculated using this formula:

  • Actual Value x Assessment Rate = Assessed Value
  • Assessed Value x Mill Levy = Taxes Due

Residential Home Example:

Actual value: $ 350,000
Assessment rate: x 7.15% (multiply by 0.0715)
Assessed value: $ 25,025
Mill levy: x 86.000 (multiply by 0.086)
Property tax: $ 2,152

Calculating Your Property Taxes

Property Tax Payments & Deadlines

Property tax exemptions for seniors and disabled veterans

Senior Tax Exemption

The Colorado Constitution establishes a property tax exemption for qualifying senior citizens, and surviving spouses of senior citizens who previously qualified. Learn more about qualifications and how to apply.

Disabled Veterans Tax Exemption

In November 2006, Colorado voters passed Referendum E – Property Tax Exemption for Disabled Veterans. This amendment to the Colorado Constitution extends the existing property tax exemption for qualifying seniors to any U.S. military veteran who is 100% permanently disabled due to a service-connected disability.

Contact Us

Phone: 303-441-3530
Fax: 303-441-4996

Business Personal Property
Phone: 303-441-3316
Fax: 303-441-1783


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Main: PO Box 471
Boulder, CO 80306-0471

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Boulder, CO 80302
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