Multiply the EAV by three. For most Illinois homes that gets you within range of what a buyer would pay, and it takes about four seconds.
Your tax bill never prints a price. It prints an equalized assessed value, and Illinois sets that at one third of market value. So the math goes backwards: EAV times three.
What is an EAV on an Illinois tax bill?
EAV stands for equalized assessed value. Your township assessor sets a value on the property, and the state then applies a yearly multiplier to the county. What comes out the other side is the EAV.
Illinois uses one third of market value as the target, per the Illinois Department of Revenue. A home the market would pay $300,000 for lands near $100,000 on that line.
Farm property works differently, and so does Cook County. Everything below is for a house in Kane, Kane’s neighbors, and the rest of the collar counties.
How do you turn an EAV into a market value?
Divide by 0.3333, or multiply by three. Both land in the same place and three is easier without a calculator.
Say your bill shows an EAV of $258,000. Times three is about $774,000. That is the value the county worked from when it built your bill.
Check yourself by going the other way. One third of $774,000 is $258,000, which is where you started.
Why is the county’s number lower than what a buyer would pay?
Because it describes an older market. Your assessor works from sales that already closed, three years of them, so the number always looks back.
In a market where prices climb, that gap opens a little wider every year. The county catches up one cycle at a time, and it is never caught up on the day you want to sell.
The reverse happens too. When prices fall, the county’s number can be the high one for a year or two.
What throws the math off?
Four things, and the first one catches almost everybody.
Exemptions. The homestead exemption comes off the EAV before your tax gets figured. Grab the number after exemptions and your answer lands low, so use the EAV line itself.
The multiplier. The state publishes an equalization factor for each county every year. Outside Cook County it usually lands at or near 1.0, which is why plain times-three works here.
A new build. The first bill on new construction can reflect a bare lot. Multiply that and you get the value of the dirt.
A recent appeal. A win at the Board of Review lowers your assessed value without lowering what a buyer would pay for the house.
What does this look like in Kane County?
Kane County works from the same one third of market value, and the Kane County Assessment Office publishes the figure for every parcel. Township assessors do the field work behind it.
The value math is the same in every town here. What changes from Elgin to Geneva to Batavia is the tax rate applied to it, and the school district drives most of that. Our post on Kane County property tax rates lists the composite rate by district.
So two houses with the same EAV, ten minutes apart, can owe the county different amounts.
What should you do with the number?
Times three gives you a rough figure and nothing more. It does not know that you redid the kitchen, or that your back yard drops down toward the Fox River.
A price comes from what similar homes near you sold for in the last few months, adjusted for the ways yours differs. That is a separate job from the one your assessor does, and it is the number that decides your list price.
If you want that figure for your own house, ask for it. Our what’s my home worth page gives you an estimate from recent sales nearby. Dale will go over it with you and tell you where the estimate is off.
Call or text Dale at (630) 940-7016 with your address and he will send back what the market says.
