How do you change penalty calculation from IRS to TurboTax software?

[sonzoil]

Hello.

For my 2025 taxes I opted to let the IRS determine my penalty for underpayment of taxes.  Before I file, how do I go back into the software, and change my preference to allow me to use TurboTax to calculate it? I tried, but nowhere does the software allow me to make the change...

[DoninGA]

To change or update the Underpayment penalty -

Click on Federal Taxes (Personal using Home & Business)

Click on Other Tax Situations

Under Additional Tax Payments

On Underpayment penalties, click the start or update button

[sonzoil]

Yes, I tried that.  The screen response was "No underpayment penalties based on entries you don't have a penalty for underpayment of estimated taxes" then it asks me if I want to review estimated taxes.  When I was going through the software initially I allowed the IRS to determine my penalty.  With how much I now owe, and what I paid total in estimated taxes in 2025, it seems I should be getting some kind of penalty.

[DoninGA]

@sonzoil On your Form 1040 if Line 38 is blank (empty) and you do owe an Underpayment penalty the IRS will calculate the penalty and send you a bill in the mail.

Is there an amount on Line 38?

[sonzoil]

No, line 38 is blank.