The maximum amount of an employee's disposable earnings subject to child support withholding is 60 percent of his or her pay, or 50 percent if the employee is already making payments to support other children or spouses. Both of these percentages increase by 5 percent if an employee is 12 or more weeks in arrears in making support payments.

To calculate disposable earnings, subtract all legally mandated deductions from an employee's gross pay, such as federal and state income taxes, Social Security and Medicare taxes, and any locally mandated disability or unemployment taxes. Voluntary deductions, such as pension and medical insurance deductions, are not used to calculate disposable earnings.

Example. The Dim Bulb I.Q. Testing Company receives a court order to withhold child support payments from the pay of its employee Ernest Evans, in the amount of $390 per weekly paycheck. The payroll manager needs to determine how much can actually be withheld from Mr. Evans's pay, who earns $850 per week and does not make support payments to another child or spouse. His typical paycheck remittance advice is:

Of the amounts listed on the remittance advice, the medical insurance and 401 (k) deductions are voluntary and so cannot be included in the calculation of disposable earnings. This increases Mr. Evans's disposable earnings to $625. The payroll manager then multiplies this amount by 60 percent, which is the maximum amount of disposable earnings that can be remitted for child support. The result is $375, which is $15 less than the $390 listed on the court order. The payroll manager begins deducting and remitting $375 per week.

When a child support court order is received, it takes precedence over all other types of garnishment orders, with the exception of tax levies that were received prior to the date of the court order. An employer must begin withholding the maximum allowable amount from an employee's pay no later than the first pay period beginning 14 working days after the posted date of the court order, and must continue to withhold funds until the order is rescinded by the court.

A common point of confusion is where to send child support payments. Contrary to any demands by the parent who is designated to receive the payments, they typically go to a court-designated person, who then disburses the funds to the recipient parent—payments never go straight to that parent. Instructions for remitting funds will be listed on the court order; the employer should follow these instructions to the letter.