This is my first year filing for more than two jobs. Why when I add my third w-2 my federal and state refund drop drastically

[Hal_Al]

More income, means more tax and possibly at a higher tax rate.  A drop in the amount on the "refund meter" would be normal.  Wait til the end and review your form 1040 for accuracy. 

[sugamama2008]

It might be the amount of federal/state taxes that were withheld, or more specifically the amount that wasnt withheld from your wages. the more income the higher you go in the tax brackets. this increases your tax liability (how much you are responsible to pay) from the higher bracket. thus reducing refunds or increasing amount due.

[VolvoGirl]

Yes that is common. It just looks that way because you put them in as separate W2s and saw the tax due change in between them. If it was all on one W2 you would get the same result. And each job was withholding like it was your only job.

Because you only get one standard deduction no matter how many W2s you enter. Turbo Tax starts out by giving you the Standard Deduction. You entered more income when you entered the second W2 but you didn’t enter more deductions. And each job only withheld taxes like it was our only job for the year. You might want to adjust your withholding. Also as you add more income you might not be getting as many credits as before like the EIC credit.