Illinois's top marginal state income tax rate is 4.95%. State tax is progressive here, so most filers pay an effective rate well below the top figure — the calculator applies a blended approximation rather than modeling the full bracket schedule.
Second-highest effective property tax rate in the country. Statewide median household income is $80,000, which is the default loaded above.
Remember that a state with no income tax is not automatically cheaper overall. Illinois has an effective property tax rate of 2.05% and average homeowners insurance of $1,900 a year — states without wage income tax typically recover revenue through property or sales taxes.