@KrisD15 You are correct. Now I understand how this number is calculated. My son has investment income, plus summer intern scholarship issued in 1099-misc form by the school to pay for summer research project -housing and food. Those numbers add up equal to child unearned income in form 8615. There is only number in Box 1 about $65k, no number in box 5 in form 1098T. In form 8615, I have to enter parents income in Part II, it calculates tentative tax rate based on the parents' income, this tax then added to the child tax in Part III which drives the total tax significantly higher. Someone mentioned that parents income doesn't need to be included in the child tax if select "parents will not claim child as dependent" although child "can" be claimed as dependent. Does it sound right to you?
