Rates/Penalties/Interest

What is the current tax rate?

Individual Income Tax rates:
Tax Year Ending	Rate
1990 through 2007	3.00%
1989	2.75%
1985 through 1988	2.50%
1984	2.75%
1983	3.00%
1969 through 1982	2.50%

You will owe a late-payment penalty for underpayment of estimated tax if you were required to make estimated payments and failed to do so, or failed to pay the required amount by the payment due date. You may be penalized even if you are receiving a refund. If your Illinois Income Tax exceeds the total tax withheld and credited (Line 16 minus the total of Lines 17, 19, 20b, 21b, 22b and 23) for the tax year by more than $500, you may have been required to make estimated payments. The penalty rate is based on the number of days the payment is late. For more information refer to Form IL-2210, Computation of Penalties for Individuals.

Is there a penalty if I do not pay my tax return by the due date?

You will owe a late-payment penalty for unpaid tax if you do not pay the tax you owe by the original due date of the return, even if you have an extension of time to file. The penalty rate is based on the number of days the payment is late. For more information refer to Form IL-2210, Computation of Penalties for Individuals.

How do I calculate interest?

You will compute interest on tax from the day after the original due date of your return through the date you pay the tax and penalties. Interest is simple interest figured using a daily rate. The rate is reviewed twice each year - on January 1 and July 1 - and adjusted according to the "underpayment rate" or the "short-term federal rate" established under the Internal Revenue Code (IRC), Section 6621.

For interest accruing on or after January 1, 2004, the rate of interest payable on overpayments and underpayments is the "short-term federal rate" for the first year that the overpayment or underpayment accrues interest. This rate is 3 percent less than the "underpayment rate." After one year, interest will accrue on any remaining balance at the "underpayment rate."

For interest accruing on or after January 1, 1994, and before January 1, 2004, the rate is the "federal underpayment rate." To obtain the current interest rate, See current interest rate.