@MayaD The estate/trust tax rates was quickly repealed back in 2019. For 2020 and beyond, the kiddie tax returns to pre-TCJA rules wherein a child's unearned income is taxed at the parent's marginal tax rate. For 2018 and 2019, a child could choose between TCJA rules and pre-TCJA rules for computing the kiddie tax. https://www.nolo.com/legal-encyclopedia/kiddie-tax-limits-shifting-unearned-30003.html
@zeeph You are correct, the first $1100* is not taxed, remaining $1100 is taxed at 10%. After that the parent's rate is applied. The calculation is complicated. Look closely at form 8815 (or 8814) to see what's happening.
*Actually it's not always $1100. The amount covered by the student's standard deduction is not taxed. A student's standard deduction is $1100 or his earned income +$350 (but not more than $12,550). Scholarship income is earned income for purposes of the standard deduction, but unearned income for the kiddie tax tax-rate application.
