In Wisconsin, parents have an obligation to support their child financially until the child is 18 years old. This support obligation can extend to age 19 if the child is in high school ("pursuing an accredited course of instruction leading to the acquisition of a high school diploma or its equivalent"). Wis Stats. § 767.511(4). Termination of child support when the child "ages out," however, does not happen automatically. Sometimes the county Child Support Agency contacts the parents and then moves to terminate child support. But ultimately, the burden is on the parents to make sure child support terminates at the appropriate time. If the Child Support Agency does not act on your behalf, you may need to file a motion and obtain a court order terminating child support.
If you pay child support and your child is nearing the age when your obligation to pay child support ends, pay attention to your case. Contact your attorney or your county Child Support Agency to ensure that your child support does not continue to accrue after your obligation to pay support has ended. If you miss the termination date and over-pay child support, you may be able to recoup the overpayment by filing a motion and asking the circuit court to order repayment. But this is a time-consuming and potentially expensive remedy that is best avoided by ensuring that your child support terminates when it should.
If you have more than one child, it may be in your interest to seek modification of child support as each child approaches age 18/high school graduation. Before you do so, though, calculate your prospective child support obligation based upon the parties' current financial circumstances to be sure the amount of child support you pay will decrease. For example, if your income has increased significantly since entry of the previous child support order, a recalculation of child support may actually increase your support obligation, even though you will be paying support for fewer children.