Enterprise
Individual & Small Business
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Federal 2026 estimated tax due dates, for comparison: April 15, 2026, June 15, 2026, September 15, 2026, January 15, 2027.
Who must pay Mississippi estimated tax?
Every individual taxpayer who does not have at least eighty percent (80%) of his/her annual tax liability prepaid through withholding must make estimated tax payments if his/her annual tax liability exceeds two hundred dollars ($200).
How do you avoid a Mississippi underpayment penalty?
Estimated tax payments (plus withholding) must not be less than 80% of the annual income tax liability; underestimates or late payments incur interest of 1/2% per month. A prior-year-tax safe harbor was not confirmed on the DOR page (see Form 80-320 for exceptions).
How much should you pay?
Start with your federal estimate: the free Quarterly Estimated Tax Calculator works out your 2026 federal payments and safe harbor. Mississippi figures its own tax, so the state amount is separate.