St. Clair County property tax calculator 2026
This St. Clair County property tax calculator provides an estimated property tax based on market value, the Illinois statutory assessment level of one-third of fair cash value, and a combined local property tax rate. The result is an estimate and actual tax bills may differ depending on the applicable taxing districts and exemptions.
Estimates only. Loan terms and approval depend on lender underwriting.
Many U.S. counties use multiple local taxing authorities (county, city, school district, special districts). Enter your combined local millage rate as shown on your annual property tax notice.
Estimated property tax
Enter the market value to see the estimated annual property tax.
How it works
In Illinois, most real property is required by statute to be assessed at one-third of its fair cash value. This estimator multiplies the market value by one-third to determine assessed value. The assessed value is then multiplied by the combined local property tax rate, which reflects the total rate of overlapping taxing districts such as the county, municipalities, school districts, and special districts.
Examples
The calculation follows a structured formula: market value multiplied by one-third to determine assessed value, and then multiplied by the combined local property tax rate entered by the user. Because tax rates vary depending on the specific taxing districts that apply to a property, the combined rate must reflect the correct location.
Limitations and important notes
This calculator provides an estimated property tax only. Combined local tax rates vary by taxing district within St. Clair County. Exemptions such as general homestead, senior, disability, or veteran-related exemptions are not automatically applied. The official tax bill issued by the county treasurer may include adjustments not reflected in this estimate.
FAQs
How is property tax calculated in St. Clair County?
Property tax is calculated as market value multiplied by the statutory one-third assessment level and then multiplied by the combined local property tax rate applicable to the property’s taxing districts.
What assessment level does Illinois law require?
Illinois law generally requires most real property to be assessed at one-third of its fair cash value, which is applied in this estimator.
Is there one countywide property tax rate?
No. The total rate depends on the combination of county, municipal, school district, and other local taxing districts that apply to the property.
Does this tool show my official tax bill?
No. This tool provides an estimated property tax based on market value and a combined local rate. The official tax bill may include exemptions or other adjustments not reflected here.
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Calculations are simplified and for guidance only. Always double-check results and current rules with official sources or a qualified professional before making financial decisions.