I am not a professional accountant or CPA. But from my experience as a self-employed (in the US), you are in “safe harbor” if you just plan to pay at least 90%

I am not a professional accountant or CPA. But from my experience as a self-employed (in the US), you are in “safe harbor” if you just plan to pay at least 90% of last year’s tax bill (spread throughout the year) and then estimate any additional taxes due in January prior to the April deadline based on end of year totals. Again, it’s just a suggestion, so discuss this with your tax accountant.