@sdh11 , I think I misread your earlier post as indicating that the large capital gain was in January 2024.
All you need to do to meet the safe harbor for 2025 is make sure that that at least 25% of 110% of your 2024 tax liability. That would mean paying 27.5% of your 2024 tax liability each quarter. Of course you could pay all 110% in Q1 if you like. What I usually do is pay the 27.5% for each of the first 3 quarters, then in early January do a a calculation of my expected actual tax liability and adjust the Q4 estimated tax payment downward if I can do so while still avoiding a Q4 underpayment.
