My salary compensation and, thus, my maximum withholdings, are a small fraction of my compensation. For 2020 I was covered by the safe harbor rule. For 2021, I'll need estimated tax payments.
I tried using my preliminary numbers to compute them. TurboTax Premier (web version) gives me four identical payments. My income, though, varies from quarter to quarter. Last year, the best quarter was 40% higher than the worst. I want to use the annualized income installment method so I can pay a more accurate amount each quarter. I don't mind doing the extra work.
I don't see an option. Anything else I find in the fora and on the Internet seems to refer to a desktop version of TT. Am I missing something? Am I out of luck? I am also wondering if I'll be prevented from computing estimates from scratch after I file on April 15.