If my parents claim me as a dependent (I am a full time student and work) will my refund be smaller and by how much?

[DDollar]

The real question should be "Can you be claimed as a dependent on someone else's tax return?"  If you can be claimed, then you are required to check the box that you can, whether they claim you or not.  As for will your refund be smaller if someone else can claim you, the answer is, It Depends.  It depends on what kind of income you had and how much of it you had.  The Standard Deduction for individuals that can be claimed as a dependent is the lesser of  (1) $12,000 or (2) the greater of $1,050 or $350 plus the indvidual's unearned income.  Unearned income is then taxed at the same rates as Trusts or Estates, which can be higher than what an individual filing as Single would pay.  So, if all your income was earned, maybe not.  If you had unearned income, then you would be paying more than if you couldn't be claimed as a dependent.