I pay estimated taxes quarterly and I take my RMD fully in January. After eading all the suggestions on how to deal with putting back the RMD my situation was simplified because all my taxes come from me and not anyone else via withholding.
In June I transferred my RMD money back to my IRA (I use Fidelity). When I filed I noted that I took the RMD and put it back. My 1040 had the word 'ROLLOVER' and my AGI did not have any RMD included. My return, other than some extra numbers on page one essentially was as it would have been had I never even taken out the RMD.
The only issue was that since I had paid two quarterly estimated tax payments based on my taking the RMD I had fully paid my 2020 taxes by the 2nd payment. So I made no estimated payments in September and January. Of course the IRS had a few thousand extra dollars of mine that I was due back. But that was easy since I really didn't need the money. I just told them to apply the overage to my 2021 payments. If I asked for them to send it back to me I would have received it in March maybe and then have to send it back again on April15th as my first quarter payment. So now I can send in a bit less for the 2nd quarter payment too.
