Self employed

You cannot pay retroactively.  You can make an estimated tax payment and the TurboTax software will determine if an underpayment penalty is owed.

There are two safe harbors you should be aware of:

1. if your spouse has withheld 100% of your 2021 tax liability or
2. together you withhold 90% of your current 2023 tax liability

then, you will not owe an underpayment penalty.