How to Calculate 2017 Illinois State Income Tax by Using State Income Tax Table

1. Find your income exemptions

2. Find your pretax deductions, including 401K, flexible account contributions ...

3. Find your gross income

4. Check the 2017 Illinois state tax rate and the rules to calculate state income tax

5. Calculate your state income tax step by step

6. If you want to simplify payroll tax calculations, you can download ezPaycheck payroll software, which can calculate federal tax, state tax, Medicare tax, Social Security Tax and other taxes for you automatically. You can try it free for 30 days, with no obligation and no credt card needed.

Learn more about the in house payroll tax solution for Illinois small businesses here.
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Illinois State Tax Tables

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 Important Tax Due Dates>

2018 Illinois State Tax Witholding Table
2017 Illinois State Tax Witholding Table
2016 Illinois State Tax Witholding Table
2015 Illinois State Tax Witholding Table
2014 Illinois State Tax Witholding Table
2013 Illinois State Tax Witholding Table
2012 Illinois State Tax Witholding Table
2011 Illinois State Tax Witholding Table
2010 Illinois State Tax Witholding Table

IRS released the new 2018 tax tables on Jan 11, 2018. Employers should implement the 2018 withholding tables as soon as possible, but not later than February 15, 2018.

Current ezPaycheck software clients and ezAccounting software clients can download the latest version for free to update 2018 tax tables.

Tax rate used in calculating Illinois state tax for year 2017

State Abbreviation:


State Tax Withholding State Code:


Acceptable Exemption Form:


Basis For Withholding:

State Exemptions

Acceptable Exemption Data:

0 / Number of Regular Allowances / Number of Additional Exemptions

TSP Deferred:


Special Coding:

Determine the Total Number Of Allowances field as follows:
First Position - Enter 0 (zero).
Second and Third Positions - Enter the number of exemptions claimed.

Determine the Additional Exemptions Claimed field as follows:
First and Second Positions - Enter the number of additional allowances claimed on Line 2 of the IL-W-4. Valid values are 00 through 99. If no allowances are claimed, enter 00.

Additional Information:


Withholding Formula (Illinois Effective 2017)
  1. Subtract the biweekly Thrift Savings Plan contribution from the gross biweekly wages.

  2. Multiply the adjusted gross biweekly wages times 26 to obtain the annual wages.

  3. Determine the exemption allowance by applying the following guideline and subtract this amount from the annual wages.

    Exemption Allowance = $2,175 x Number of Exemptions

  4. Determine the additional allowance by applying the following guideline and subtract this amount from step 3 to compute the taxable income.

    Additional Allowance = $1,000 x Number of Additional Exemptions

  5. Multiply the taxable income computed in step 4 times 3.75 percent to determine the amount of Illinois tax withholding.

  6. Divide the annual Illinois tax withholding by 26 to obtain the biweekly Illinois tax withholding.

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