Can I ask my boss for a copy of the W2 form that I filled out before starting employment?

I think what you are wanting is a W-4. Is there an HR department? Is the payroll function outsourced to a third party? If there is an HR department, or if the payroll function is being done by another company, it would be advantageous to request it from them. You may need to fill out a new W-4, then turn it into whomever does the payroll function.

Your pay stub can act like a preliminary W-2; however, as Chris stated, you'll need to fill out a new W-4 to change your exemptions and increase/lower the amount of taxes being withheld.

I would add be clear in explaining the problem you are trying to solve, "why so much taxes are being deducted". You should reconfirm the W-4 was properly filled out and at the same time have some one explain the salary caps associated with some of the taxes etc. As a new employee, your the social security fica tax is reset. You may have reached it in prior job and saw an increase in your take home. Hope this help

Anonymous--sure you can ask but why? Fill out a new w-4 form, make yourself a copy so next time you have it and turn in the new original. Time to move forward. The past is not relevant at this time.

I would reiterate Vernon Reizman's comment, although its late in the year. You may want to make the adjustment for the first payroll of 2014.

Also, if Malak Kazan's scenario is correct (i.e., you've started a new job and are starting the OASDI portion of your FICA again from "Dollar One" at the new job after reaching the cap at your old job), keep in mind that you can apply the extra FICA you're paying at the new job as a credit against your federal income tax. This is very often overlooked by tax preparers, though most computer-prep software should handle it correctly.

If you decide you want to file the new W-4 for what remains of 2013, and you are overpaying your FICA as described in the aforementioned paragraph, drop me a line and I'll walk you through what you need to do.

You can go to http://www.irs.gov and under Forms and Pubs on the left hand side you can click on Form W-4. The worksheet that is included does a good job for most people of figuring out how they should fill out the form. The website also has a calculator online to help you out. Just type in "IRS Withholding Calculator" in the search field at the top of the IRS website.

I disagree about waiting. You are giving the IRS a loan when you withhold more than you need. It might also take you a while to figure out what you should be doing. Don't forget to check on your state's website as well.

Sometimes your paycheck stub will show your status and exemptions. Look for a code that shows up something like S 1, S 0 (single 1/0 exemption), or M 4, M 8 (married 4/8 exemptions). I hope this makes sense. It is likely to be in a header or footer section of the stub and not associated with any particular amount.

I agree that the sooner you adjust it, the better, and filling out a new form is the way to go. You cannot modify the old one anyway, you would still have to fill out a new one. Good luck.