Taxes from a 401 k to Roth conversion

[Mary136]

I converted a 401k to a Roth IRA 4th Q 2024.  How do I pay the taxes now so that  I don't get hit with an underpayment fine?

[Opus 17]

Two steps.

First, make an estimated payment before January 15, 2025 at www.irs.gov/payments.

Then, when you prepare your tax return, perform the penalty interview (it may not come up automatically) and select the "annualized" method.  This will complete form 2210 Schedule AI, to divide your income by quarters and show that even though your payments were unevenly loaded into the last quarter, they matched your income that was also unevenly loaded in the last quarter. 

[Mary136]

Thank you Opus 17th.  Very helpful, especially the second part!