Property Tax Simulator Tool

The Cook County Assessor's Property Tax Simulator tool, PTAXSIM, is a publicly available software package in R that can approximate the effects of assessments, levies, TIFs, and other inputs on Cook County property tax bills.  

PTAXSIM uses code and a database of property tax data for Tax Years 2006 through 2020 (bills payable from 2007 through 2021) to recalculate tax bills for one or multiple properties. It can also produce counterfactual historical property tax scenarios, such as analyzing the property tax impact of exemptions or TIFs in one city or township.   

This package and the included database are for educational purposes only. The Assessor’s Office releases the package and database without any representations or warranties of any kind, whether express or implied. Any data, figures, or amounts contained within the package/database, used by the package/database, or produced by the package are solely for illustrative purposes and do not imply policy recommendations by the Assessor’s Office. 

Any results produced by this package as distributed are not official, as they are hypothetical, and should not be relied upon for any business or commercial purpose. The Assessor’s Office expressly disclaims any liability for any entity’s reliance on this package and/or database.

Access PTAXSIM

For questions and feedback, please contact Assessor.Data@cookcountyil.gov.