Form 80-320-17-8-2-000 (Rev. 10/17)
Mississippi
Individual Income Tax
Interest and Penalty Worksheet Instructions
Use Form 80-320 if your 2017 Mississippi income tax liability exceeds $200 to calculate interest on underpayment of estimated tax. This
form is also used to calculate late payment interest and penalty, and the late filing penalty for the Resident Individual Income Tax Return
(Form 80-105), the Non-Resident/Part-Year Resident Return (Form 80-205) and EZ Individual Income Tax Return (Form 80-110).
Specific Line Instructions
Exceptions
Gross income from farming or fishing is at least two-thirds of total gross income and (a) estimate tax paid by the 15th day of
the first month after the close of the income year or (b) income tax return is filed by the first day of the third month following
the close of the income year and tax shown due is paid.
Filing requirements met after payment due date - compute interest in applicable columns and provide an explanation below.
Underestimate
Line 1
Enter your 2017 Mississippi net income tax liability from Form 80-105, line 20, (Resident), Form 80-205, line 22
(Non-Resident/Part Year) or Form 80-110, line 6 (EZ). If your 2017 Mississippi Income Tax Liability is $200 or less, do not
complete the remainder of this form; no interest is due on underestimate of tax.
Line 3
Enter your 2016 Mississippi net income tax liability from Form 80-105, line 20, (Resident), Form 80-205, line 22
(Non-Resident/Part-Year) or Form 80-110, line 6 (EZ).
Line 4
Enter the lesser of line 2 or line 3. If line 3 is zero and your 2017 Mississippi income tax liability (line 2) exceeds $200
and no estimate payments for the 2017 tax year were made, enter the amount from line 2.
Late Filing Penalty
Line 13 Enter late filing penalty due. Add penalty of 5% per month, not to exceed 25% in the aggregate, from the extension
due date of the return, October 15th, on the amount of net tax due from Form 80-105, line 34 (Resident) or Form 80-205,
line 35 (Non-Resident/Part-Year) or Form 80-110, line 18 (EZ). The penalty shall not be less than $100.
Late Payment Interest and Penalty
Line 14
Enter balance due. From Form 80-105, line 34 (Resident) or Form 80-205, line 35 (Non-resident/Part-Year) or
Form 80-110, line 18 (EZ).
Line 15
Enter late payment interest due. Add interest of 6/10 of 1% per month from the original due date of the return, April 15th,
on the amount of tax due from line 14.
Line 16
Enter late payment penalty due. Add penalty of 1/2% per month, not to exceed 25% in the aggregate, from the original due
date of the return, April 15th, on the amount of tax due from line 14.
Enter the total late payment interest and penalty by adding line 15 and line 16.
Line 17
Total Interest and Penalty
Line 18
Enter the total interest and penalty by adding line 11 plus line 13 and line 17. Enter here and on Form 80-105, line 35
(Resident), or Form 80-205, line 36 (Non-Resident/Part-Year) or Form 80-110, line 19 (EZ).