I converted $12000 to backdoor Roth for previous year before April

[weafrique]

I converted a total of $12000 to backdoor  in 2022 before April. Of which $6000 was for the previous year 2021. What do I enter here $6000 or $12000? My tax refund decreases when I enter $6000 but corrects when I enter $12000, however  it says I owe a penalty because $6000 is being considered as an excess, although it was my contribution for the previous year.

[DavidD66]

You can only enter $6,000 per year to a Traditional IRA; therefore, you enter $6,000.  You should have entered $6,000 for your 2021 contribution on your 2021 tax return.  If you did not, you will need to amend your 2021 tax return.  You covert all $12,000 (or any other amount) in 2022.  Once you finish reporting the entire Back Door Roth it should have no impact on your tax due/owed, as long as you don't have any other traditional IRAs.  If you have other (non-Roth) IRAs, then a portion of your Back Door Roth will be taxable.