Why did my federal tax go up from 2019 to 2020, even though I take the standard deduction, and my adjusted gross income was actually a bit less in 2020 than in 2019?

[MayaD]

It is hard to tell why you might owe more this year without being able to look at your return.  Here are some of the common reasons :

• You didn't have enough taxes withheld from your paychecks. 
• You lost a dependent.
• You changed your filing status.
• You did not qualified for the full amount of the Child Tax Credit. If you don't have any Tax liability you will only receive the additional Child Tax Credit. 
• You didn't qualify for the Earned Income credit. 

[gmulry · Accepted solution]

I figured it out. I had underestimated my income when choosing an Obamacare policy. Therefore, I have to pay back some of the premium help I received. TurboTax figures that from the 1095 form, but it was not immediately apparent what was going on--until I went to the actual forms, rather than my usual way of completing the federal form by simply answering Turbotax questions, and letting the Turbotax do the final check for any errors.