Illinois Tax Estimator

There is no single Illinois property tax rate

Illinois does not have one rate — it has 102. They run from 0.82% in Pulaski County to 2.68% in Lake County, with the median county at 1.85%. That is the first thing to understand before comparing Illinois against anywhere else: a state average is an average of things that do not resemble each other.

The gap between the cheapest and dearest county here is more than 3.2 to one on the same house. A spread that wide is not explained by state law, because state law is identical throughout — it comes from the local mix: how much of the school budget the state funds rather than the district, whether there is commercial or industrial value to spread the burden across, and how fast home values have moved relative to the budgets those values must fund.

On a $400,000 home the difference between the two ends of Illinois is roughly $7,409 a year, every year you own it. Pick your county below rather than reasoning from the state figure.

How Illinois compares with the rest of the country

Illinois sits above the national picture. Its median county charges 1.85% against a national median of 0.84%, so an owner here generally pays more than in most of the United States on the same house.

For scale, US effective rates run from about 0.08% to 3.64% across the 3,132 counties with published data — more than twenty to one on the same property, decided almost entirely by which side of a line it stands on.

A more useful measure than the rate is what it takes out of a local income. Across Illinois counties the median bill averages about 3.9% of median household income.

The Illinois rules that decide your bill

Start with what is actually taxed, because in Illinois it is not the market value. Illinois assesses at one third of fair cash value statewide — except Cook County, which runs its own classification and puts residential at 10% of market value while commercial sits at 25%. The state then applies a county equalization factor, the multiplier, to pull each county back to the 33⅓% the law requires. That is why an Illinois bill shows an 'equalized assessed value' that matches neither the price nor the assessment. On a $400,000 home that is roughly $133,320 of taxable value before any exemption comes off.

Illinois’ general homestead exemption is capped at $10,000 of equalized assessed value in Cook County and less elsewhere in the state. Because Illinois works in equalized assessed value rather than market value, the shelter in market terms is roughly three times that. In most counties it is not applied automatically — you have to claim it, and an owner who never filed goes on paying the unrelieved amount indefinitely with nothing on the bill to tell them.

Owners 65 and over get a further $8,000 reduction in Cook County and the contiguous counties. The Senior Freeze goes further and locks the equalized assessed value in place for as long as you keep qualifying — the income limit for it rose to $75,000 for 2025.

These are Illinois rules and they apply in every county in the state. What varies locally is the rate, not the relief — so if you qualify and have not claimed it, your county assessor is where that gets fixed, not the state.

Property tax and income tax in Illinois, together

Illinois taxes income as well as property, at a flat 4.95%. The two are set by different authorities — income by the state, property by your county — and they answer different questions, so it is worth adding them rather than comparing them.

States trade one off against the other. A low income tax is often paired with heavier property tax and the reverse, which is why a comparison built on a single tax so frequently gives the opposite of the right answer. Our income tax calculator covers the Illinois side of that.

What a house actually costs in Illinois, at four prices

At the median county rate of 1.85%, a $250,000 home carries about $4,616 a year, a $400,000 home $7,386, a $600,000 home $11,079, and a $900,000 home $16,619. Property tax is close to linear in value, which income tax is not — doubling the house roughly doubles the bill.

But the median is the wrong number to plan with, because you do not buy in the median county. That same $600,000 house costs $4,948 a year in Pulaski County and $16,062 in Lake County — a difference of $11,114 every year, on identical property, under identical state law.

Over a ten-year hold that gap compounds to $111,138 before any rate increase. It is larger than most buyers' entire closing-cost budget, and it is decided by which side of a line on a map the house sits on. That is the case for looking up the county rather than the state.

One caution on all four figures: they apply the effective rate to the full purchase price. Where the state assesses at a fraction of market value, or caps how fast the assessed value can climb, your first-year bill and your fifth-year bill will differ from this — the sections below say exactly how, for Illinois.

Where each Illinois county sits, in four groups

Ranking Illinois's 102 counties by effective rate puts the quarter boundaries at 1.56% and 2.07%, with the median at 1.85%. Crawford County sits on the lower boundary and Champaign County on the upper — anything below the first is cheap for this state, anything above the second is expensive for it, and the middle half falls between the two.

On a $126,100 house those boundaries are $1,962 and $2,610 a year: a difference of $648 between the bottom quarter and the top, ignoring the extremes at either end entirely. Half of all Illinois counties fall inside that band, which is the honest answer to "what does property tax cost here" — a range, not a number.

Against the country, 1 of 102 Illinois counties sit below the national median of 0.84% and 101 above it. A state that straddles the national median this way cannot be summarised as cheap or expensive — the county decides it, which is the whole argument for looking one up.

Two cautions on reading the quartiles. They rank rates, not bills: a low rate on an expensive house can exceed a high rate on a cheap one, and the counties at the bottom of this ranking often have the highest home values. And they rank the county, while your bill is the sum of every district reaching your parcel — a house inside a city or a high-spending school district pays above its county's figure.

Why Illinois rates differ by 3.2× under identical law

Property tax runs backwards from every other tax you pay. Income tax starts with a rate and produces revenue; property tax starts with the revenue a district needs, divides it by the total assessed value in the district, and the rate is whatever falls out of that division. Nobody sets 1.85% — it is a quotient.

Two things move it, and only two: the budget on top and the tax base underneath. That is why a rate can fall while your bill rises — if assessed values across the district climb faster than the budget, the rate must drop to collect the same money, and the owner whose property gained the most value still pays more. It is also why a district losing its largest employer sees rates rise with no vote and no new spending.

The base is what explains Illinois's spread. Pulaski County raises what it needs at 0.82%; Lake County needs 2.68% for comparable services. The usual difference is not extravagance — it is commercial, industrial or utility value that spreads the load away from houses, a district where it is present and one where houses carry nearly all of it.

School funding is the other half. Where a state funds most of education centrally, local rates converge; where districts raise it themselves, they diverge, and the poorest base needs the highest rate to fund the same school. Nationally, counties run from 0.46% at the tenth percentile to 1.57% at the ninetieth for precisely this reason.

Market value, assessed value and the number on your bill

Illinois assesses at one third of fair cash value statewide — except Cook County, which runs its own classification and puts residential at 10% of market value while commercial sits at 25%. The state then applies a county equalization factor, the multiplier, to pull each county back to the 33⅓% the law requires. That is why an Illinois bill shows an 'equalized assessed value' that matches neither the price nor the assessment.

In practice: a $126,100 house in Illinois is taxed on roughly $42,029 of assessed value, not on $126,100. The published millage is applied to that smaller figure, which is why a headline rate that looks alarming next to another state often is not — the two are being applied to different bases.

This is exactly why every rate on this site is an EFFECTIVE rate: tax actually paid divided by the home's market value. It is the only figure that survives comparison across state lines, because it has the assessment ratio, the exemptions and the millage already folded into it. A nominal millage does not.

It also explains a common shock. Assessment ratios and reassessment cycles differ, so a state can reassess every year, every three years, or on sale only. Where reassessment is infrequent, the correction when it finally arrives is not a rate increase — it is several years of market movement landing at once, and appealing the rate rather than the value is arguing the wrong point.

The Illinois homestead exemption, in dollars

Illinois’ general homestead exemption is capped at $10,000 of equalized assessed value in Cook County and less elsewhere in the state. Because Illinois works in equalized assessed value rather than market value, the shelter in market terms is roughly three times that.

Put in money at the median county rate of 1.85%, $10,000 off the taxable value is worth about $185 a year — $1,846 over a decade you stay in the house. On the state's median home value of $126,100 it removes roughly 7.93% of the taxable base.

The part that costs people real money: in most states this is not automatic. It attaches to your primary residence and generally must be claimed once, after you take ownership — and a buyer who never files simply pays the higher figure indefinitely, with no notice that anything is missing. If you bought in the last two years, check your assessment notice for the exemption line before assuming it is there.

It also lapses. Convert the house to a rental, move out and keep it, or inherit it without re-filing, and the exemption comes off — sometimes with the county reclaiming prior years. Where a state ties an assessment cap to homestead status, losing the status also releases the cap, and the bill can jump by far more than the exemption was ever worth.

Appealing a Illinois assessment: what it is worth

You cannot appeal the tax rate — that is set by budget votes you have no standing to challenge individually. What you can appeal is the assessor's opinion of your property's value, and that is a factual claim you can be right or wrong about.

The arithmetic decides whether it is worth your afternoon. On the state's median home of $126,100, the bill runs about $2,328 a year. A 10% reduction in assessed value is worth roughly $233 a year, and because the corrected value carries forward it is nearer $1,164 across five years. Under $60 a year, the paperwork rarely pays; over $400, it usually does.

What wins is comparable sales, not hardship. Three to five recent arm's-length sales of genuinely similar properties — same neighbourhood, similar size, age and condition — near your valuation date. What loses is what the bill does to your budget, what the previous owner paid, or that the rate went up. Assessors decide value; none of those speak to value.

Also check the record itself before arguing valuation, because errors are commoner than contested opinions: square footage that includes an unfinished basement, a bathroom that does not exist, a garage counted twice, land area from a survey predating a lot split. A factual correction is usually granted without a hearing.

Deadlines are set locally here and are short — often thirty to forty-five days from the date the assessment notice was mailed, not from when you read it. Check the notice itself for the date, because missing the window generally forfeits the year regardless of how strong the case was.

Relief for older owners in Illinois

Owners 65 and over get a further $8,000 reduction in Cook County and the contiguous counties. The Senior Freeze goes further and locks the equalized assessed value in place for as long as you keep qualifying — the income limit for it rose to $75,000 for 2025.

This matters more than the headline rate for anyone retiring in place. Property tax is the one major tax that does not fall when your income does — the house is worth what it is worth whether you are earning $120,000 or drawing $38,000 from a pension, and a bill that was 3% of income while working can be 9% of it afterwards.

Relief of this kind almost always has to be applied for, is usually income-tested, and in several states takes the form of a deferral rather than a discount: the tax is postponed and becomes a lien recovered when the property is sold or transferred. A deferral solves a cash-flow problem and reduces what heirs receive. Both can be the right choice; they are not the same choice, and the paperwork rarely spells out which one you are signing.

Check it against the income-tax side too. A state that treats retirement income generously and property harshly, or the reverse, can come out very differently once both are counted — which is what the comparison further down this page is for.

The ten-year figure, which is the one that decides a purchase

A single year's property tax is a number people accept without much thought. The decade is the number that changes decisions, because unlike a mortgage it never amortises away and unlike income tax it does not fall when your income does.

On Illinois's median home value of $126,100, held ten years with assessed value rising 4% a year, the median county collects about $27,955. The cheapest county in the state collects $12,486 over the same period and the dearest $40,529 — a spread of $28,043 on identical property, decided entirely by location.

The same house at the national median rate of 0.84% would run $12,673 over ten years, so the median Illinois county costs about $15,282 more across the decade than a typical American county would.

Set that against the mortgage to see the weight of it. On a $126,100 purchase the ten-year property tax bill in the median county is roughly 28% of the amount financed at 80% loan-to-value — before insurance, before maintenance, and before any millage increase. It is the largest recurring cost of ownership after interest, and the only one that a district can raise without asking you.

Treat the figure as an order of magnitude rather than a forecast. It assumes the county's current effective rate holds, and rates move with district budgets and with reassessment cycles. What it is reliable for is the comparison: the gap between two counties is far more durable than either absolute number.

How the bill is paid, and what happens if it is not

Most owners with a mortgage never pay this directly. The servicer collects roughly $194 a month alongside principal and interest on the state's median bill, holds it in escrow, and pays the county when it falls due. The consequence is that a rise reaches you as a change in your monthly payment months after the fact, with no obvious connection to the assessment notice that caused it.

Read the annual escrow analysis when it arrives. It shows the bill actually paid, and it is the cheapest way to catch an assessment you would have appealed had you noticed — by the time the payment changes, the appeal window for that year has usually closed.

Owners without a mortgage pay the county directly, generally in two instalments. Late payment carries interest set by statute rather than by the county, and it is not small — rates in the region of 1% a month are common, which is above most credit card debt on an annualised basis.

Unpaid property tax is also secured against the house itself, which is what separates it from every other tax. States permit a tax lien, and eventually a tax sale, at the end of a statutory redemption period. It is slow and heavily noticed, so it is nearly always avoidable — but the mechanism means an unpaid property tax bill can never simply be written off the way an unpaid income tax debt sometimes is.

Five ways a Illinois property tax estimate goes wrong

Using the state average. Illinois has 102 counties with published rates and they do not resemble one another. The state figure is an average of things that are not alike, and applying it to a house in Lake County understates the bill by $1,047 a year.

Applying the millage to the market price. Where assessed value is a fraction of market value, multiplying the published rate by the purchase price overstates the result — sometimes by half. Use an effective rate, which already accounts for the base.

Assuming exemptions are automatic. Illinois's homestead exemption generally has to be claimed after purchase, and nothing on the bill announces that it is missing. Buyers who never file pay the unexempted figure for as long as they own.

Comparing property tax in isolation. Illinois also taxes income, so a property-only comparison against a no-income-tax state reaches the wrong conclusion in one direction — and against a high-income-tax state, the wrong conclusion in the other. Both taxes or neither.

Trusting the listing's tax line. It is the seller's bill, carrying their tenure and their exemptions. Where a sale triggers reassessment it is not a forecast of yours, and it is the single most common reason a first full-year bill arrives higher than budgeted.

How a Illinois property tax bill is put together

Your bill is not one rate. It is the sum of every authority that reaches your parcel — the county, the school district, the city or township, and often a fire, library or water district — each setting its rate separately and all of them added together. That is why two houses of identical value on opposite sides of a district line inside the same county owe different amounts, and both figures are correct.

The effective rates on this site are a different and more comparable thing: the median tax actually paid in a county divided by its median home value, from US Census data. That number can be compared across state lines. A millage rate cannot, because assessment practice differs from state to state — and Illinois, taxing 33.33% of value, is a good example of why.

Use the county figure to compare places and to sanity-check an escrow estimate. Use your assessor's roll to find out what you owe.

Illinois property tax questions

What is the average property tax rate in Illinois?

The median Illinois county has an effective rate of 1.85%, but the state average hides a lot: rates run from 0.82% in Pulaski County to 2.68% in Lake County. Use your own county's figure rather than the state one.

Which Illinois county has the lowest property tax?

Pulaski County, at 0.82%. The highest is Lake County at 2.68% — a difference of about 3.2 to one on the same house.

How much is property tax on a $400,000 home in Illinois?

At the median county rate of 1.85%, roughly $7,386 a year, or about $615 a month once it is in escrow. In Pulaski County it would be nearer $3,299 and in Lake County nearer $10,708.

Is there a homestead exemption in Illinois?

Yes, and it is set statewide. Illinois’ general homestead exemption is capped at $10,000 of equalized assessed value in Cook County and less elsewhere in the state. Because Illinois works in equalized assessed value rather than market value, the shelter in market terms is roughly three times that. You have to claim it in most counties.

Does Illinois have an income tax too?

Yes — a flat 4.95%, on top of the property tax on this page. Worth adding both before comparing Illinois against another state.

Do I need a parcel number to estimate Illinois property tax?

No. Your county assessor's own estimator generally asks for one, which is fine if you already own the property and useless if you are deciding whether to buy it. This works from the home value instead — though for the binding figure, the assessor remains the authority.