On my tax return I added the $600 stimulus from 2021 by accident. Will this affect my 3rd stimulus check?

[MinhT1]

This will not affect your third stimulus payment.

In fact, you have to report both stimulus payments on your 2020 tax return, even if your receive the second payment in 2021.

In fact, both these payments are advanced payments of the 2020 Recovery Rebate Credit.

Please read this IRS document on the Recovery Rebate credit.

If you made a mistake in reporting the amount of stimulus received, the IRS will most likely identify the error and adjust your refund.

Please read the answer to question E1 of this IRS Q & A.

[BillMar472]

Great specific answer with the reference. Thanks