Hello! To answer your questions: If the Adjusted Gross Income (AGI) on your previous year's return is over $150,000 (over $75,000 if you are married filing separately), you must pay the lower of 90% of the tax shown on the current year's return or 110% of the tax shown on the return for the previous year. To determine the amount, you look at the total tax due/liability, not total tax withheld. It is best to pay taxes throughout the year as opposed to all in one quarter. You can choose to make a payment online and designate it as an estimated payment for 2024 so that you get some extra tax paid in during the quarter of the conversion.
Here is a link to a great article that you can review regarding when and how much to pay if you have additional income and will owe tax:
https://turbotax.intuit.com/tax-tips/small-business-taxes/estimated-taxes-how-to-determine-what-to-p...
(This article is not only for those in business, but is a great discussion of estimated payments generally.)
Here is another link regarding how to avoid IRS penalties. It discusses the fact that our system is a "pay as you go" system, meaning it is generally best to pay taxes throughout the year, as stated above.
https://turbotax.intuit.com/tax-tips/irs-letters-and-notices/guide-to-irs-tax-penalties-how-to-avoid...
Good luck!
