How much is withheld from an employee's paycheck?
Each new employee must complete a Form W-4 as soon as he/she reports to work, so that Federal withholding tax can be correctly computed. The W-4 must include a complete Social Security Number and will remain in effect until that employee completes a new form.

Some states have their own required version of a withholding certificate, so you should check with the state to see what is required.

If an employee does not complete a W-4 Form, the employer is required to withhold as if the person was claiming single with zero allowances. An employee must not alter the language of the W-4, and must sign it to make it a valid form.

Generally, income tax must be withheld from all wages paid to employees. The amount to be withheld is computed each pay period.

You should not withhold from someone who claims exempt on the W-4. Any worker who claims this status must complete a new W-4 each year by February 15th. Anyone who claims more than 10 exemptions must be reported quarterly to the Internal Revenue Service.