Q. Will I have to pay tax on the full 12k?
A. Yes, because your other income ($15,500) exceeds your standard deduction ($14,600 for 2024). This means that any additional income is fully taxed, at your marginal rate.
Q. At how much percentage?
A. Most at 10%. Some will be 12% (or 22%, see next question).
Q. My mom can claim me on her taxes as well if this makes any difference?
A. Yes. Taxable scholarship is considered unearned income* and subjects you to the "Kiddie tax", wherein part of your income is taxed at your parent's marginal tax rate (probably 22%), rather than your marginal rate (12%).
Housing is not an eligible expense, for scholarship money to be tax free, but books and other course materials (including a computer) are. So, the difference between box 1 and box 5, on the 1098-T is not necessarily the taxable amount.
There is another other issues. Is your mom eligible to claim the tuition tax credit (is her income not too high, usually $90K, $180K married filing jointly). See separate discussions, below.
*Scholarships are a hybrid between earned and unearned income. It is earned income for purposes of the $13,850 filing requirement ($14,600 for 2024) and the dependent standard deduction calculation (earned income + $400 ($450 for 2024)). It is not earned income for the kiddie tax and other purposes (e.g. EIC). For grad students and post grad fellows, scholarship, stipend and fellowship income is earned income ("compensation") for IRA contributions.
