TurboTax does not calculate your penalties and interest for late filing or late payment. That will be calculated by the IRS based on when they receive your return and how much tax you owe. You will receive a bill from the IRS with the amounts.
Hi,
Here is an article regarding your question: https://ttlc.intuit.com/turbotax-support/en-us/help-article/tax-penalties/irs-penalty-miss-october-16-extension-filing/L3zHKxTys_US_en_US
The IRS applies late penalties and interest on a case-by-case basis and will send a separate bill if penalties apply. Because the IRS has the last word on penalties, we can't calculate the exact amount if your return is late. But the info below will give you an idea of what to expect in a worst-case scenario.
Interest (compounded daily) starts accumulating on unpaid taxes one day after the due date of the return, until the bill is fully paid off. The current interest rate is 6% and is subject to change.
Thank you,
John
CPA