It's best to just make payment of the tax liability that TurboTax indicates is due at the time of your filing. The IRS will then determine if a late fee is due, as well as calculate it for you. You'll receive a notice from the IRS by mail.
*** I am NOT a tax expert. I am a seasoned TurboTax user, and volunteer to provide assistance to TT users. Nothing I post is to be considered TAX ADVICE; I bear no legal liability for responses.***
