35 ILCS 5/101 to 5/1701
The Illinois Income Tax is imposed on every individual, corporation, trust, and estate earning or receiving income in Illinois. The tax is calculated by multiplying net income by a flat rate. The Illinois Income Tax is based, to a large extent, on the federal Internal Revenue Code (IRC).
Effective January 1, 2011, the current rate is 5 percent of net income. Click here for prior year rates.
Your Illinois income includes the adjusted gross income (AGI) amount figured on your federal return, plus any additional income that must be added to your AGI. Some of your income may be subtracted when figuring your Illinois base income.
The base income earned in Illinois or while a resident of Illinois is then reduced by the number of federally claimed exemptions and any additional exemptions.
The amount of each federally claimed exemption is $2,000, and the additional exemptions are $1,000 each for any taxpayer or spouse who was either 65 years of age or older, legally blind, or both.
The total exemption amount is deducted from base income to arrive at “net income.” The tax rate is then applied against net income.
Form/Filing & Payment Requirements
The requirements are similar to federal income tax procedures, including withholding and payments of estimated tax.
— Form IL-1040,
filing period is the same as your federal filing period. The due date most individuals, this April 15th.
— You must make estimated income tax payments if you reasonably expect your tax liability to exceed $500 after subtracting your Illinois withholding, pass-through entity payments, and tax credits for income tax paid to other states, Illinois Property Tax paid, education expenses, the Earned Income Credit, and Schedule 1299-C, Income Tax Subtractions and Credits (for individuals). You will likely need to make estimated payments if your income is either fully or partially exempt from Illinois withholding.
You do not have to make estimated payments if you are 65 years or older and permanently living in a nursing home or a farmer. We consider you a farmer if at least two-thirds of your total federal gross income is from farming.
For most individuals, estimated payments are due April 15th, June 15th, September 15th, and January 15th of the following year. For individuals using fiscal year reporting, payments are due on the 15th day of the fourth, sixth, and ninth months of the fiscal year, and of the first month after the end of the fiscal year. Individuals must complete Form IL-1040-ES, Estimated Income Tax Payments for Individuals, and mail it with their estimated tax payments.
Note: If payments are made by an electronic method do not complete or mail Form IL-1040-ES.
Automatic extension payment — We grant an automatic six-month extension of time to file your return. If you receive a federal extension of more than six months, you are automatically allowed that extension for Illinois. These extensions do not grant you an extension of time to pay any tax you owe. If you determine that you will owe tax, you must file Form IL-505-I, Automatic Extension Payment for Individuals, to pay any tax you owe to avoid penalty and interest on tax not paid by the due date.
Note: If payments are made by an electronic method do not complete or mail Form IL-505-I.
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