IRS released the new early release copies of the income-tax withholding tables for 2014 on Dec 2013.

For 2014, the annually one withholding allowance increased to $3,950.
For 2014, the employee and employer tax rate for social security is 6.2%. The social security wage base limit increases to $117,000.
More tax rate changes can be found here

2014 Federal tax tables
http://www.halfpricesoft.com/federal_income_tax_2014.asp 

Thanks,

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