- 1). Multiply the number of personal allowances you claimed on your W-4 form by the value of each allowance. For 2010, each personal allowance reduces your income subject to tax withholding by $3,650, but this amount changes each year for inflation. For example, if you claimed two allowances, you would have your annual income subject to withholding decreased by $7,300.
- 2). Divide the annual value of you personal allowances by the number of pay periods per year. For example, if you are paid weekly, you would divide by 52. Continuing in the example, you would divide $7,300 by 52 to find your weekly pay subject to withholding would be $140.38 less than your total pay.
- 3). Subtract any pretax deductions taken out of your paycheck such as traditional 401k contributions or pretax health care costs. For example, if you had $240.62 in pretax deductions you would subtract that from your weekly salary.
- 4). Calculate your tax withholding amount by using the federal income tax withholding tables for the current year. The 2010 withholding tables are attached as a resource. For example, if you had $700 in weekly income after taking out your personal allowances and pretax expenses and were single, you would have $84.10 withheld for federal income taxes.
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