The Child Tax Credit is affected by the amount of your income.

Per IRS Publication 972 Child Tax Credit and Credit for Other Dependents, on page 4:

Limits on the CTC and ODC

The maximum credit amount of your CTC or ODC may be reduced if either (1) or (2) applies.

1. The amount on line 18 of your Form 1040, 1040-SR, or Form 1040-NR, is less than the total of both credits. If this amount is zero, you cannot take either credit because there is no tax to reduce. But you may be able to take the ACTC if you are claiming the CTC (you cannot take the ACTC if you are only claiming the ODC). See Additional Child Tax Credit (ACTC), later.
2. Your modified adjusted gross income (AGI) is more than the amount shown below for your filing status.
   a. Married filing jointly – $400,000.
   b. All other filing statuses – $200,000.

Modified AGI. For purposes of the CTC and ODC, your modified AGI is your AGI plus the following amounts that may apply to you.

• Any amount excluded from income because of the exclusion of income from Puerto Rico. On the dotted line next to Form 1040 or 1040-SR, line 11, enter the amount excluded and identify it as “EPRI.” Also attach a copy of any Form(s) 499R-2/W-2PR to your return.
• Any amount on line 45 or line 50 of Form 2555, Foreign Earned Income.
• Any amount on line 15 of Form 4563, Exclusion of Income for Bona Fide Residents of American Samoa.

If you do not have any of the above, your modified AGI is the same as your AGI.

AGI. Your AGI is the amount on line 11 of your Form 1040, 1040-SR, or 1040-NR.

Note that any link in the information above is updated each year automatically and will take you to the most recent version of the document at the time it is accessed.