Per IRS:
Dependent filing requirements:
Single dependent who is not age 65 or older or blind:
Must file a return if any of the following apply.
Unearned income was more than $1,250.
Earned income was more than $13,850.
Gross income was more than the larger of:
$1,250, or
Earned income (up to $13,450) plus $400.
irs.gov
The link you have posted is for Kiddie Tax.
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