After you file


@Fil78 wrote:
Do you have to refile 2018 taxes if you forgot to report $4 of misc income?

Technically, you would amend, if anything, and you are required to report all of your income, regardless.

 

It is entirely possible that your tax liability will not change when the $4 is added, but it is also possible for your tax liability to increase by a multiple of that $4 at higher income levels.

 

Therefore, you should input the $4 into your return, before doing anything else, and verify that it does not increase your tax liability (make sure you save the TurboTax .tax2018 file  that you submitted to the IRS to another location so you do not accidentally overwrite it while testing).