Follow the steps to fill out the MS Form 80-320 online.

1. Click 'Get Form' button to obtain the form and open it in the online editor.
2. Begin by entering your personal details in the Taxpayer section, including your first name, initial, last name, and Social Security Number (SSN). If applicable, also include the same information for your spouse.
3. Next, provide your mailing address, including the street number and name, city, state, and ZIP code.
4. Indicate if you are a farmer or fisherman by selecting the appropriate option if relevant.
5. In the ‘Filing Requirements Met After Due Date’ section, enter the County Code as instructed.
6. Calculate your 2024 Mississippi income tax liability and fill it in the corresponding field.
7. Multiply the amount from the previous line by 80% and enter the result.
8. Enter your 2023 Mississippi income tax liability in the designated area.
9. Enter the lesser of the previous two calculations on the appropriate line.
10. Proceed to calculate required installments, and enter 1/4th (.25) of the lesser amount computed previously.
11. Provide details on income tax withheld and estimated tax paid in the subsequent fields.
12. Complete the fields for overpayment or underpayment and carry forward any amounts as instructed.
13. Calculate underestimates subject to interest and follow through with the calculations for percentage of interest.
14. Continue filling out the lines for interest due, late filing penalty, and total amounts as required.
15. Finally, review all entries for accuracy, then save changes, download, print, or share the completed form.

Start filling out your MS Form 80-320 online today to ensure accurate tax calculations.