@Critter-3 Thanks, you are correct.
Now I know:
1) Backdoor Roth conversion activity is reported on current calendar year's tax return; while IRA contribution can be done for previous year, as long as it is done before deadline (around April 15).
2) Yes, based on what I have learned, I can always do backdoor roth conversion for current year, if I am uncertain about my income. I was asking the question, since I am not familiar with so many things, just in case of messing some tax forms. I really support flat tax rate without so many loophole. It makes things complicated, but I still need to know the loophole of backdoor roth conversion, in order to take advantage of loophole.
Thanks again, I have learned a lot about backdoor Roth conversion after this post. Now I need to summarize some note, in case of forgetting it in the future.
