What actually sets Illinois apart
Illinois bills are the product of a levy divided across a tax base, not a fixed rate, so a falling market can raise your rate while your value drops. The number of overlapping districts on a single Illinois parcel — county, township, municipality, school, park, library, fire, sanitary — is among the highest in the country, and each one is a separate line on the bill.
Property taxes in Illinois at a glance
- Average effective tax rate: 2.07% of home value per year
- Median home value: $250,500
- Estimated tax on a median-value home: $5,189 per year (about $432 per month)
- Rank by tax rate: 2nd of 50, highest first
- Rank by amount actually paid: 6th of 50, highest first
- Where these figures come from: U.S. Census Bureau, American Community Survey 5-year estimates, for the Illinois statewide averages shown above — ACS 2019-2023 5-year estimates, last reviewed September 2026.
What the Illinois rate leaves out
Illinois is 2nd of the fifty by rate and 6th by the bill a median-value owner receives — a shift of 4 places, and the $250,500 median home value is what causes it. The rate is a reasonable shorthand here, but it is not the whole answer, and both numbers are worth checking before comparing Illinois with anywhere else.
How Illinois works out what you owe
Most of the state assesses at one third of market value. Cook County is the exception and uses its own classification system, assessing residential property at 10% of market value.
The Property Tax Extension Limitation Law caps the growth of most non-home-rule districts' extensions at 5% or the rate of inflation, whichever is less, without a referendum.
Exemptions Illinois homeowners should claim
Each of these reduces an Illinois bill every year you hold the property, and almost none are granted without a claim:
- General homestead exemption: Reduces the equalized assessed value of an owner-occupied primary residence.
- Senior citizen exemption and assessment freeze: An additional exemption from age 65, plus an income-tested freeze that holds the equalized assessed value at its qualifying-year level.
Where you buy inside Illinois changes the bill
A statewide average hides its extremes. Where they show up in Illinois:
- Cook County: its own classification system and triennial reassessment cycle, plus the equalization factor applied to bring assessments into line with the rest of the state
- Lake County: consistently among the highest effective rates in the United States, driven by school district levies
- DuPage County: high absolute bills on high values, with a large number of overlapping special districts on each parcel
Illinois and its neighbours
The same $250,500 — the Illinois median — taxed at each neighbouring state's average rate:
- Wisconsin at 1.51%: about $3,783 a year, roughly $1,406 less than the $5,189 an Illinois owner would pay on the same value.
- Iowa at 1.43%: about $3,582 a year, roughly $1,607 less than the $5,189 an Illinois owner would pay on the same value.
- Missouri at 0.88%: about $2,204 a year, roughly $2,985 less than the $5,189 an Illinois owner would pay on the same value.
- Kentucky at 0.77%: about $1,929 a year, roughly $3,260 less than the $5,189 an Illinois owner would pay on the same value.
- Indiana at 0.74%: about $1,854 a year, roughly $3,335 less than the $5,189 an Illinois owner would pay on the same value.
Appealing an Illinois assessment
If the assessed value on your Illinois home overstates what it is worth, the route is an appeal to the county Board of Review, then the Illinois Property Tax Appeal Board. The window is within 30 days of the publication of the township assessment roll, and it is strict — missing it means waiting a full cycle.
Frequently asked questions
When are Illinois property taxes due, and when must exemption claims be filed?
Taxes are paid a year in arrears, with instalments commonly due in the spring and the autumn. Applications are filed with the county assessor or supervisor of assessments; the income-tested freeze must be renewed each year.
Does this calculator use my exact Illinois county tax rate?
No — it applies the Illinois statewide average of 2.07%. Rates are set locally, and the spread inside Illinois is wide enough to matter: on a $250,500 home, $2,716 a year separates Illinois from an averagely taxed state before any county variation is counted. Check the parcel's own rate with its Illinois county before relying on this figure.
Reference sources
Related calculators
How this estimate is built
Principal and interest come from the standard amortization formula, worked through in full on the formula reference page. Property tax, insurance, PMI and loan-program figures layer on top from published assumptions — each one sourced, dated and listed on the methodology page. Every result here is an estimate built from public data, not a quote: confirm the specifics with a lender before relying on it.
For developers
This calculation is also available as a REST API and through an MCP server, both running the same engine as this page — so the figures match by construction rather than by convention. No key required.