2024 Cook County Final Multiplier or Equalization Factor Set
On Thursday, May 29, 2025, the Illinois Department of Revenue announced a final 2024 Cook County Equalization Factor of 3.0355. This final 2024 Cook County Equalization Factor is 0.64% higher than the 2023 Cook County Equalization Factor of 3.0163. The final 2024 Cook County Equalization Factor is 6.56% higher than the tentative 2024 Cook County Equalization Factor set on May 13, 2025 of 2.8487.
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 (2021-2023) of the actual selling prices of individual properties to the assessed value placed on those properties by the county assessor. 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 by the Illinois Property Tax Code. A 1.00 factor means that the assessments are accurate and in line with the statewide standard. A 3.0355 factor indicates that the assessments as a percentage of market value are significantly lower than required, and therefore, a large upward adjustment is needed to equalize them to the state’s mandate of a 33 1/3 percent level of assessment.
In their press release issued by the DOR, the average three-year level of assessment is 10.55% for Class 1 (vacant properties); 9.04% for Class 2 (residential) properties; 7.86% for Class 3 (apartment) properties, 21.63% for Class 5A (commercial) properties and 23.47% for Class 5B (industrial) properties. The three-year average level of assessments (weighted by class) for Cook County property is 10.98%. 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 10.98% to calculate the final equalization factor of 3.0355.
The date when the second installment 2024 real estate tax bills will be issued has not been set as of the current date.
Rieff Schramm Kanter & Guttman LLC provides reliable advice that can lower your tax burden. To schedule an appointment, call or contact our Chicago office online for a free consultation.
