Spreadsheet to estimate 2013 US Federal Income Tax withholding based upon IRS Notice 1036. For tax advice consult a tax professional. All use is strictly AS IS with no warranties implied or expressed. Creative Commons Share-alike license.
2013-withholding Free download, use at your own risk.
The tables were apparently based upon the annual table. Bi-Weekly tables are the annual tables divide by 26 and rounded to whole numbers. The Daily table is the Annual table divided by 260 and rounded to one decimal. Each row designates one “tax bracket”. For each higher bracket, taxpayer is charged the tax for the next lower bracket and then taxed upon their income within their own bracket: they do not appear to be taxed on all the lower brackets, only the bracket immediately below their own.
Social Security and Medicare Tax for 2013
The employee tax rate for social security is 6.2%. Previously, the employee tax rate for social security was 4.2%. The employer tax rate for social security remains unchanged at 6.2%. The social security wage base limit is $113,700. The Medicare tax rate is 1.45% each for the employee and employer, unchanged from 2012. There is no wage base limit for Medicare tax. Employers should implement the 6.2% employee social security tax rate as soon as possible, but not later than February 15, 2013. After implementing the new 6.2% rate, employers should make an adjustment in a subsequent pay period to correct any underwithholding of social security tax as soon as possible, but not later than March 31, 2013. http://www.irs.gov/uac/Notice-1036,-Early-Release-Copies-of–the-Yearly-Percentage-Method-Tables-for-Income-Tax-Withholding
More information on FICA, Medicare, FUTA, SUTA, to follow. In the meantime, here is a Forbes article on the impact of the Affordable HeatheCare Act (Obama Care) via IRS rules. http://www.forbes.com/sites/rickungar/2013/02/04/irs-ruling-to-create-millions-of-uninsured-americans-as-it-undermines-the-very-intent-of-obamacare/?google_editors_picks=true