The amount you receive for the stimulus check will need to be reported on your 2020 tax return as income.
What do I need to know about the coronavirus stimulus package?
the actual credit will be calculated based on your 2020 return form that there will be subtracted the advance you got. if you're due more of a credit it will increasse your refund or decrease the balnce due.. at the present time if the advance you got is more than the credit allowed it appears that you will not have to pay it back or pick it up as income.
See interview from Kiplinger's - there could be a claw back if your 2020 AGI (I guess including the stimulus award) exceeds the $150,000 threshold
Ryan Ermey: A couple of quick ones before we let you go here, Rocky. One, just to clarify for all the people out there, unless you have that kind of discrepancy that you talked about between 2020 and 2019, you're never probably going to have to pay any of this money back, right, because it's a tax credit?
Rocky Mengle: Well we, again, we don't know that for sure. Again, if your stimulus check is higher than the 2020 credit amount, there's a chance that the IRS will come back and say, "Hey, we want that money back. You got more than what you were supposed to get." The Cares Act authorizes the IRS to adopt some rules and regulations that are to avoid allowing multiple credits, or rebates and taxpayers. So they might try to use that authority to claw back that amount. We just don't know. We're waiting for guidance from the IRS on that. Just one of those areas that hasn't... questions that hasn't been answered yet.