see this thread for some info on ES and safe harbor calculation
https://ttlc.intuit.com/community/taxes/discussion/re-is-it-optional-or-mandatory-to-pay-estimated-t...
Normally when you file, under Other Tax Situations / Form W4 and Estimated Tax you can input estimates for 2025 to help calculate estimated tax vouchers. By default if you don't input your 2025 info then TT will generate ES vouchers based on prior year tax and assuming your 2025 withholding is the same as 2024.
You need to have paid thru the year via withholding or timely (usually quarterly) estimated taxes, the smaller of 100% of your 2024 tax (110% if AGI > 150k or 75k if Married Filing Separately), or 90% of your 2025 tax. That's your safe harbor amount. Usually paying based on prior year tax is an overpayment if your income is steady, but if you have an increase in income in 2025 it can be advantageous. Withholding is always considered timely so if you don't quite make the safe harbor you can always increase withholding but only have a few months left of the year for that to have effect. Finally, if the outcome of all this is you do owe ES, you should catch up the Q1-2 payments ASAP to stop the penalty accruing further, then resume quarterly payments for Q3/4 per the deadlines. If your income is uneven and in particularly later in the year (e.g. Roth conversion in Q4) then you an pay ES unevenly to line up with it, and file Form 2210 Annualized Income method to hopefully reduce or eliminate the penalty.
How to reduce or avoid a penalty depends your situation, but start with you doing the safe harbor calculation to see whether you need to pay ES based on prior year or current year tax.
Form 1040-ES has a worksheet to determine if you need to pay ES (but don't use 1040-ES vouchers etc to pay ES, if able pay electronically at irs.gov).
https://www.irs.gov/forms-pubs/about-form-1040-es
You will need an estimate of your 2025 AGI for the safe harbor calculation, there are various tax calculators here but I don't think updated for 2025 tax brackets or big bill changes so there may be other resources available.
https://turbotax.intuit.com/tax-tools/calculators/taxcaster/
