2023 Cook County Final Multiplier or Equalization Factor Set

The Illinois Department of Revenue has released its final 2023 Cook County equalization factor of 3.0163.  This equalization factor is 3.17% higher than the 2022 Cook County equalization factor of 2.9237.  The final 2023 Cook County equalization factor is 6.16% higher than the tentative 2023 Cook County equalization factor that was previously released at the end of February, 2024 of 2.8414.

Every year, the Illinois Department of Revenue (DOR) is legally required to calculate the equalization factor to achieve uniform property assessments throughout the state.  The DOR determines the equalization factor for each county by comparing the three-year period the actual selling price of individual properties to the assessed value placed on those properties by the county assessor.

In their press release issued by the DOR, the average three-year level of assessment is 7.40% for Class 1 (vacant properties); 9.02% for Class 2 (residential) properties; 7.40% for Class 3 (apartment) properties, 22.89% for Class 5a (commercial) properties and 23.26% for Class 5b (industrial) properties.

The three-year average level of assessments (weighted by class) for Cook County property is 11.05%.  The Illinois Department of Revenue calculates the final Cook County equalization factor or multiplier by dividing Cook County’s 33.33% level of assessment into the three-year average of 11.05 to calculate the final equalization factor of 3.0163.

If the median level of assessment for all property in the county varies from the 33 1/3 percent level of assessment required by law, an equalization factor is assigned to bring assessment to the legally mandated level as required by the Illinois Property Tax Code.  Since the 2023 final Cook County Equalization Factor has issued on May 20 this year, the second installment 2023 real estate taxes are expected to be issued timely this year which means officials are trying to have the bills issued in July and due in August, 2024.