Illinois homeowners pay a median $5,298 a year in property tax on a home worth $263,300, or 2.01 percent of value on Census figures, with county ratios from 0.96 percent in Hardin to 2.58 percent in Lake. The Illinois property tax calculator below covers all 102 counties: it applies each county’s effective ratio, the Census median bill over the median owner-occupied value, and shows the result beside the local median bill. Type fair cash value, meaning what the house would sell for, not the one third assessed value (10 percent in Cook) printed on your notice.
Levy First, Rate Second: How an Illinois Bill Is Built
In Illinois the dollars come first and the rate follows. Each taxing district decides what it needs and files a certificate of levy with the county clerk by the last Tuesday in December; asking for more than 5 percent over last year requires a truth in taxation hearing.
Illinois Property Tax Calculator (2027)
Choose any of the state's 102 counties, from Lake and Cook in the north to Hardin on the Ohio River, enter fair cash value, and see a yearly and monthly estimate at that county's effective ratio next to what its typical owner is billed. Ratios come from Census Bureau ACS 2024 5-year tables B25103 and B25077.
An estimate, not a bill: your value times the county's Census ratio (median paid over median value, ACS 2024 5-year). A real Illinois bill takes one third of fair cash value (10 percent in Cook), applies the state equalization factor, subtracts homestead exemptions such as the $6,000 general exemption ($8,000 next to Cook, $10,000 in Cook), then multiplies what remains by the aggregate rate of every district in your tax code area. Bills arrive the year after the assessment date. For the amount due, check with the county treasurer or collector; take value questions to the township assessor or the county board of review.
The clerk then sets each fund’s rate at whatever figure, times the district’s equalized assessed value (EAV), yields the levy. Rates of every district overlapping a tax code area add up to one aggregate rate, in dollars per $100 of EAV (effectively a percentage). Your bill is EAV, less homestead exemptions, times that rate.
So when values climb, rates often fall, because the same levy spreads over a bigger base. Bills rise when levies rise, or when your home gains value faster than your neighbors’.
From Fair Cash Value to EAV: One Third, Cook’s 10 Percent, and the Multiplier
State law assesses most real property at 33 1/3 percent of market value. Cook alone classifies property, assessing homes at 10 percent and commercial property at 25 percent.
The Illinois Department of Revenue compares three years of sales with assessments in each county and issues an equalization factor, the multiplier, to pull the county back to one third. Cook’s final 2025 factor, released in June 2026, is 3.0300 (3.0355 for 2024), which puts a Cook home near 30 percent of market value before exemptions.
Arithmetic only: a $300,000 home in a downstate county not bordering Cook, factor 1.0000, is assessed at $100,000; the $6,000 general homestead exemption leaves $94,000 of EAV, so each 1 percent of rate costs $940. At the 6.704 percent sample rate in the department’s own guide, the bill is $6,301.76. The same $300,000 home in Cook is assessed at $30,000, equalized to $90,900, and after the $10,000 Cook exemption carries $80,900 of EAV, or $809 per percentage point of rate.
More Than 6,000 Districts, and the Limit That Is Not a Cap
The state counts more than 6,000 taxing districts. A typical bill stacks a county, a township, a city or village, school districts, a community college, and park, fire, library, or sanitary districts. Schools take the largest share.
Home rule units (Cook County and municipalities over 25,000) face no statutory rate ceilings. For other districts in Cook, the collar counties of DuPage, Kane, Lake, McHenry, and Will, and counties that adopted it by referendum, the Property Tax Extension Limitation Law holds growth in dollars extended to the lesser of 5 percent or prior year inflation, plus new construction; for 2025 levies paid in 2026 that was 2.9 percent. PTELL restrains district revenue, not your bill: a reassessment, a lost exemption, or a voter-approved increase can still push one household up faster.
County Rates, From Lake Down to Hardin
On the Census ACS 2024 five year estimates, Lake leads at 2.58 percent, then DeKalb at 2.45 percent, Stephenson at 2.40 percent, Winnebago (Rockford) at 2.39 percent, and Kendall at 2.37 percent. At the bottom sit the Shawnee Hills and Ohio River counties of far southern Illinois: Hardin at 0.96 percent, Pulaski at 1.02 percent, and Pope at 1.03 percent.
The biggest median bills are suburban: Lake $8,923, DuPage $8,007, Kendall $7,651, Kane $7,382, McHenry $7,274, and Will $7,173. Cook is lower at 1.91 percent and $6,191. The statewide 2.01 percent tops the middle county (about 1.8 percent) because the pricey northeastern counties carry high ratios and most of the homeowners.
Calculator examples:
- Cook County, $325,000 home: 1.91 percent gives $6,207.50 a year, or $517.29 a month, just $16.50 above Cook’s $6,191 median bill.
- DuPage County, $400,000 home: 2.05 percent gives $8,200 a year, or $683.33 a month, $193 over the $8,007 median.
- Sangamon County (Springfield), $200,000 home: 1.99 percent gives $3,980 a year, about $331.67 a month, $468 above the $3,512 median.
- St. Clair County, $180,000 home: 2.03 percent gives $3,654 a year, or $304.50 a month, $11 below the $3,665 median.
A $250,000 house would cost about $6,450 a year at the Lake ratio and $2,400 at Hardin’s. Each ratio pools 2020 to 2024 survey answers, so exemptions on file are built in, while Cook’s 2024 to 2026 reassessments are only partly reflected. No county is missing.
Board of Review, Then the Property Tax Appeal Board
Outside Cook, township assessors set the first value and the county supervisor of assessments reviews it; owners whose values change get a notice. An informal talk with the assessor can fix errors in square footage without a hearing. A formal complaint goes to the county board of review, usually within 30 days after your township’s list is published (McLean County’s rule). Once the bill arrives, it is generally too late for that year.
Cook reassesses one region a year: Chicago in 2024, the north suburbs in 2025, the south and west suburbs in 2026, each township getting about six weeks (Bremen’s notices went out August 12, 2026, with a September 24 deadline). Owners can appeal to the Assessor, the Cook County Board of Review, or both.
After the board rules, you have 30 days to go to the five member Property Tax Appeal Board, or you can pay under protest and file a tax objection in circuit court, but not both.
Homestead Exemptions by County Tier, Plus the New Senior Freeze Limit
Exemptions trim EAV, and several depend on the county:
- General homestead (35 ILCS 200/15-175): up to $10,000 of EAV in Cook, $8,000 in the counties next to Cook, and $6,000 in the rest.
- Senior homestead (15-170), age 65 and older: $8,000 in Cook and its neighbors, $5,000 elsewhere.
- Low-Income Senior Citizens Assessment Freeze (15-172): holds EAV at the base year level for qualifying owners 65 and older, though a rising rate can still lift the bill.
- Veterans with disabilities (15-169): $2,500 of EAV at 30 to 49 percent disability, $5,000 at 50 to 69 percent, and the first $250,000 of EAV at 70 percent or more; World War II veterans are fully exempt from 2024.
- Persons with disabilities (15-168): $2,000 of EAV. Returning veterans (15-167): $5,000 for two years.
- Home improvement (15-180): up to $75,000 of added market value is exempt for four years.
The recent change is the freeze’s income ceiling. Senate Bill 642, signed December 12, 2025 as Public Act 104-0452, lifts the household income limit from $65,000 to $75,000 for the 2026 assessment year (bills payable in 2027), then $77,000 for 2027 and $79,000 from 2028. Bills paid in 2026 are unaffected. Cook adds a Long-time Occupant exemption: after 10 years in the home, households earning up to $100,000 see EAV growth capped at 7 or 10 percent a year.
Paying a Year Behind: Installments, Interest, and the Tax Sale
Illinois taxes are paid in arrears: value is set as of January 1 and that year’s bill arrives the next spring. Most counties use two equal installments due June 1 and September 1 (30 days after the bill date if mailed late); some set other dates or allow four payments. Cook uses accelerated billing: the first installment is 55 percent of the prior year’s total, and the second covers the rest. For tax year 2025, Cook’s installments fall due April 1 and October 1, 2026.
Late payments add 1.5 percent interest per month. Unpaid taxes go to the annual tax sale, usually in the fall, where investors bid on the lien (not the home) by offering the lowest penalty, capped at 18 percent per six months. Owners can redeem within 6 months to 2 1/2 years by property type, extendable by the buyer to three years, before a court can issue a tax deed.
What 2027 Brings: A Chicago Reassessment, Higher Freeze Limits, and New Data
The City of Chicago is due for its next triennial reassessment in 2027, and the $75,000 freeze limit reaches its first bills that year. We update the county ratios in this Illinois property tax estimator when the Census posts its next five year release, usually in December.
Data: Census Bureau American Community Survey 2024 five year release (tables B25103, B25077); Illinois Department of Revenue PTAX-1004 (January 2026), relief and PTELL pages, and Cook multiplier releases; Public Act 104-0452; Cook County Assessor and Treasurer calendars; McLean and DuPage board of review pages. Confirm amounts due with your county treasurer and take value questions to the township assessor or board of review.