Get your taxes done using TurboTax

Ultimately, both returns will be rejected until the IRS can get in touch with both of you and make the determination, unless you two come to an agreement.  The best thing is to determine the best tax advantage and you two make an agreement.

If someone else claimed you, as a dependent, inappropriately, and if they file first, your return will be rejected if e-filed. You would then need to file a return on paper, claiming yourself, if appropriate. The IRS will process your return and send you your refund, in the normal time. Shortly (up to a year) thereafter, you’ll receive a letter from the IRS, stating that your exemption was claimed on another return. It will tell you that if you made a mistake to file an amended return and if you didn't make a mistake to do nothing. The other party will get the same letter you did. If one of you doesn't file an amended return, un-claiming the exemption, the next letter, from the IRS, will require you to provide proof. Be sure to reply in a timely manner.

Winner gets the tax benefits; loser gets to pay the IRS back with penalties and interest.

Are you sure your Mom can't claim you and do you want to make this kind of hassle for both of you. With the tax law change, effective 2018, most dependents will get the same refund whether they claim themselves or not. The personal exemption has been eliminated and the standard deduction increased.

But, on the other hand, if your mom has claimed you, inappropriately, she needs to file an amended return, un-claiming you. Student status alone does not determine whether you are a dependent.  You do not need to wait until her amended return is fully processed, to claim yourself on your return. But, you still cannot e-file. You will have to mail in a paper return.

A child of a taxpayer can still be a “Qualifying Child” (QC) dependent**, regardless of his/her income, if:

1. He is under age 19, or under 24 if a full time student, including high school, for at least 5 months of the year, or is totally & permanently disabled
2. He did not provide more than 1/2 his own support. Scholarships are considered third party support and not as support provided by the student.
3. He lived with the parent (including temporary absences such as away at school) for more than half the year

So, it doesn't matter how much he earned. What matters is how much he spent on support. Money he put into savings does not count as support he spent on him self.

The support value of the home, provided by the parent, is the fair market rental value of the home plus utilities & other expenses divided by the number of occupants.

Furthermore, there is a rule that says IF somebody else CAN claim him as a dependent, he is not allowed to claim himself. If he has sufficient income (usually more than $12,200), he can & should still file taxes. In TurboTax, he indicates that somebody else can claim him as a dependent, at the personal information section.  TT will check that box on form 1040.

Even if he had less, he is allowed to file if he needs to get back income tax withholding. He cannot get back social security or Medicare tax withholding.