What are Comparable Properties?

Homes that are comparable (similar) to each other should have similar market values, and therefore similar assessed values. 

One way to evaluate whether your home has been assessed fairly, or uniformly, is to compare its assessment to the assessment of other comparable homes.

For two homes to be comparable to each other, they must be similar in:

  • location (township and neighborhood)
  • property class code
  • age
  • building square footage
  • land square footage

Other characteristics, like the type of construction, also affect whether two homes are comparable. 

Properties that are comparable should also have similar assessed values. One way to see if an assessment is fair or "uniform" is to compare the assessed value of your home to the assessed values of comparable homes. This is why it's important that the characteristics for every home are up-to-date.


Even if two homes have the same class code, they might not necessarily be comparable to each other.

Each property in the Assessor's database is categorized in a "property class code." For example, a home that is 1,600 square feet and 22 years old is a class 203 (one-story residence, any age, 1,000 to 1,800 square feet).  You can see classification examples here.

Two homes with the same class code might not necessarily be comparable. As an example, let's say your home (the Subject PIN) is in Neighborhood 40. It is a class 203 because it is 1,600 square feet and 22 years old.

Property Neighborhood Class Code Building Square Footage Building Age                                               
Subject PIN 40 203 1,600 sf 22 years  


Let's compare the Subject PIN to two neighboring PINs to see if each neighbor is comparable to the subject PIN.

Property Neighborhood Class Code Building Square Footage Building Age Comparable to subject PIN?
PIN 1 40 203 1,500 sf 23 years Yes.
PIN 2 40 203 1,100 sf 50 years No.


Neighbor PIN 2 is not comparable to the subject home. Even though the Subject PIN and PIN 2 are both class 203, this is not enough to be comparable: they are too different in square footage and age to be considered comparable.


Find Comparable Properties

The tool recommended by the Cook County Assessor's Office is Cook Viewer's Interactive Map. This is a free tool created by Cook County GIS. You can use it to find your property, then click on your property, and then click on "Compare this Property." 

First, find your property on cook viewer. Then click on it. Then click on comparable properties.

This online mapping tool will automatically apply filters based on neighborhood, class, square footage, and age to find properties that are comparable to yours. 

The comparable properties will be shown on an interactive map so you can see that property's location relative to the subject property, its characteristics, and assessment information.

This is a useful way to determine whether your home has been assessed similarly to homes that are comparable to yours.


To find properties that are comparable to yours:

Launch Cook Viewer

This online mapping tool is a useful way to compare properties and their assessed values. 

If you are using Cook Viewer to do research for an appeal of your property's assessed value, please read our guide on how to supply comparable properties with an appeal.

Sometimes the Neighborhood Search is used to find comparable properties. It is important to remember that even if two homes have the same township, neighborhood, and class, they may not necessarily be comparable. They must also be similar in characteristics like age and square footage.  Because Cook Viewer will automatically apply these filters for you, we recommend it.