How does Colorado calculate property tax?

Colorado uses a two-step system. First the assessor multiplies your home's market value by the residential assessment ratio (about 6.7% for 2024) to get assessed value. Then the combined mill levy from all overlapping taxing districts is applied to that assessed value at a rate of one dollar per thousand of assessed value per mill.

A mill is one dollar of tax for every $1,000 of assessed value. Each taxing authority — county, city, school district, fire district, and special districts — sets its own levy, and they are added together. A combined levy of 75 mills means $75 of tax per $1,000 of assessed value.

What is the Colorado residential assessment ratio?

It is the fraction of market value that is actually taxed. For tax year 2024 the residential ratio is roughly 6.7%, down from 7.15% in prior years after recent legislation. Because only a small slice of market value is assessed, Colorado has one of the lowest effective property tax rates in the country.

Who qualifies for the Senior Homestead Exemption?

Colorado homeowners aged 65 or older who have owned and occupied their home for at least 10 consecutive years can exempt 50% of the first $200,000 of market value from tax. That removes up to $100,000 of market value before the assessment ratio and mill levy are applied. Disabled veterans may qualify for a similar exemption.

Is this estimate accurate enough for budgeting?

It is a solid planning figure, but your real bill depends on the exact mill levies of every district overlapping your specific parcel and the assessment ratio in effect that year. For an exact number, check your county assessor's online parcel search or your annual Notice of Valuation.

Colorado Property Tax Estimator

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The Colorado property tax estimator converts your home’s market value into an annual tax estimate using the state’s actual two-step assessment system — not a single blended rate. Enter your value, pick a county levy, and see the assessed value, taxable amount, and monthly cost.

How it works

Colorado does not apply a tax rate directly to market value. Instead:

Assessed value = market value × the residential assessment ratio (about 6.7% for 2024). A $500,000 home has an assessed value near $33,500.
Mill levy is applied to assessed value. One mill equals $1 of tax per $1,000 of assessed value, so a 75-mill levy on $33,500 assessed value produces roughly $2,513 in annual tax.
Senior Homestead Exemption (optional) removes 50% of the first $200,000 of market value — up to $100,000 — before the ratio and levy are applied.

The estimator runs all three steps and also reports the effective rate (annual tax ÷ market value) so you can compare counties on one number.

Worked example

A $500,000 home in Denver (≈75 mills, 6.7% ratio):

Step	Value
Market value	$500,000
Assessed value (6.7%)	$33,500
Mill levy	75 mills
Annual tax	~$2,513
Monthly	~$209

Apply the Senior Homestead Exemption and the taxable assessed value drops by about $6,700, trimming the annual bill by roughly $500.

Notes and tips

Colorado’s 64 counties each set their own combined mill levy, so the same home can cost noticeably more in Pueblo than in Douglas County.
Since the Gallagher Amendment was repealed in 2020, assessed values track market values during each two-year reassessment cycle, so bills can rise in fast-appreciating areas even when levies stay flat.
Always confirm the exact levy and current assessment ratio with your county assessor or the Colorado Division of Property Taxation before budgeting.