Do you make over 100k per year and switched jobs? If so you may have overpaid on you social security taxes.
Even though it's not included when we talk about marginal tax rates all employees have to pay 6.2% of their gross income to Social Security and 1.45% for Medicare.
The employee tax rate for social security is 6.2% (amount withheld). The 2007 wage base limit was $97,500. For 2008, the wage base limit is $102,000 or 6,324. The problem is, your employers have no idea what you're making at your other jobs, or when you reach that cap.
If you worked for two or more employers and had too much withheld, you can claim the excess as a credit on your taxes. You do this on form 1040, line 67 or form 1040A, line 43.
An example of this. You worked for a company that paid you $58,000 during 2008 and withheld $3,596 (6.2% of $58,000) in Social Security tax. You then found a better opportunity and worked for another employer who paid you $57,000 and withheld $3,534 of Social Security tax (6.2% of $57,000). Thus, the Social Security tax withheld totaled $7,130. That's $806 more than you actually owe ($7,130 minus $6,324). So you're entitled to a credit of $806.
It is not even worth trying to get your employer to stop withholding Social Security taxes if you "know" you're over the limit already They just keep withholding as if that was your only job.
One way to stop from paying too much to the tax man is to change your total tax withholding (increase exemptions, etc.) in order to counteract this overpayment and keep your money now instead of getting a future refund.
Source of information http://www.irs.gov/publications/p15/index.html
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