If you qualify for repayment protection, the amount of repayment relief you will qualify for is determined by the full repayment protection amount. The full repayment protection amount is calculated as $2,000 multiplied by the difference between the number of qualifying children the IRS initially considered for your advance Child Tax Credit payments and the number of qualifying children you can properly claim on your 2021 tax return.
For example, if the IRS initially considered three qualifying children for your advance payments but you can only claim one qualifying child on your tax return, the full repayment protection amount would be $2,000 multiplied by (3 - 1), which equals $4,000.
However, the actual amount of repayment relief you receive may be reduced or phased out based on your modified adjusted gross income (AGI). The repayment protection amount is adjusted according to how much your modified AGI exceeds the threshold for full repayment protection for your filing status. If your modified AGI is above this threshold, the repayment protection amount will be reduced accordingly.
In summary, the repayment relief you qualify for is up to the full repayment protection amount, which is $2,000 per child not claimed on your tax return, subject to reduction based on your modified AGI.
Sources:
Publication 971 (12/2021)
Publication 3 (2023)