The purpose of this application is to help employees to ensure that they do not have too much or too little income tax withheld from their pay. It is not a replacement for Form W-4, but most people will find it more accurate and easier to use than the worksheets that accompany Form W-4. You may use the results of this program to help you complete a new Form W-4, which you will submit to your employer.
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Who Can Benefit From This Application?* Employees who would like to change their withholding to reduce their tax refund or their balance due;
* Employees whose situations are only approximated by the worksheets on the paper W-4 (e.g., anyone with concurrent jobs, or couples in which both are employed; those entitled to file as Head of Household; and those with several children eligible for the Child Tax Credit);
* Employees with non-wage income in excess of their adjustments and deductions, who would prefer to have tax on that income withheld from their paychecks rather than make periodic separate payments through the estimated tax procedures.
Source: Internal Revenue Service
