How Is Child Support Determined When Parents Are Unmarried?

 Posted on January 31, 2026 in Family Law

When unmarried parents separate, child support can feel complicated and confusing. Unlike divorce cases where the court automatically addresses child support as part of the proceedings, unmarried parents must take specific legal steps to create enforceable support orders.

According to the U.S. Census Bureau, more than 40 percent of children are born in the United States to unmarried parents. In Wisconsin, thousands of unmarried parents navigate child support issues every year. Whether you are seeking support for your child or facing a support obligation in 2026, knowing how the system works is the firm step. Our experienced Milwaukee child support lawyers are here to help.

Do Unmarried Parents Have the Same Rights as Married Parents?

Unmarried parents generally have the same legal rights and responsibilities as married parents when it comes to their children. Both parents have the right to spend time with their children and participate in important decisions about their upbringing. Both parents also have the legal obligation to financially support their children.

Wisconsin law recognizes two types of custody. Legal custody refers to the right to make major decisions about your child's life, including choices about education, healthcare, religious upbringing, and other significant matters. Physical placement refers to where the child lives and the schedule for spending time with each parent.

When parents share legal custody, they must work together to make major decisions affecting their children. In some cases, one parent may have sole legal custody if they have been the primary decision-maker or if the other parent is absent or unfit. Physical placement can be shared between parents or primarily with one parent, depending on what serves the child's best interests.

The key difference for unmarried parents is that these rights and responsibilities are not automatic. The biological father must establish legal paternity before the court will recognize his parental rights and obligations.

Why Is Establishing Paternity Important for Child Support?

Paternity establishes the legal father-child relationship. When parents are married at the time of birth, Wisconsin law presumes the husband is the legal father. For unmarried parents, paternity must be established through other means before child support orders can be created.

Under Wisconsin Statutes Section 767.62, paternity can be established in several ways:

• Both parents sign a Voluntary Paternity Acknowledgment at the hospital or later through the Wisconsin State Vital Records Office

• A court orders genetic testing to confirm biological paternity

• A judge issues an order of paternity after a court hearing

Establishing paternity protects everyone involved. For the child, it creates legal ties to both parents, opens access to benefits like Social Security and health insurance, and provides a complete family medical history. For mothers, it enables them to pursue child support orders. For fathers, it grants them legal rights to spend time with their children and participate in raising them.

How Does Wisconsin Calculate Child Support?

Wisconsin uses percentage-based guidelines to calculate child support obligations. These guidelines appear in Wisconsin Statutes Section 767.511 and apply to both married and unmarried parents.

The calculation starts with the gross income of the parent who will pay support. Gross income includes wages, salaries, commissions, bonuses, self-employment income, investment income, unemployment benefits, workers' compensation, and most other sources of money. The court then applies a specific percentage based on the number of children:

• 17 percent of gross income for one child

• 25 percent of gross income for two children

• 29 percent of gross income for three children

• 31 percent of gross income for four children

• 34 percent of gross income for five or more children

Shared Placement Adjustments for Child Support 

Wisconsin recognizes that when children spend substantial time living with both parents, both parents incur direct costs of raising them. In shared placement situations where the child lives with each parent for at least 25 percent of the year, the court uses a different calculation method.

The court calculates what each parent would owe under the standard percentage guidelines if they were the paying parent. These amounts are then offset based on the percentage of time the child spends with each parent. The parent with the higher obligation pays the difference to the other parent.

Can Child Support Orders Be Changed After They Are Established?

Child support orders can be modified when circumstances change "substantially." Either parent can ask for a modification if there has been a substantial change in circumstances since the original order.

Common reasons for modification include:

• A parent experiences a significant increase or decrease in income

• A parent loses their job or becomes disabled

• The physical placement schedule changes significantly

• The child's needs change due to medical conditions, educational requirements, or other factors

You should always file a formal modification request with the court rather than making a verbal agreement with the other parent. Child support obligations continue to accrue according to the court order until the court officially modifies them. You cannot retroactively reduce support payments you agreed to skip or reduce informally.

What Happens If a Parent Does Not Pay Child Support?

When a parent can’t or won’t pay court-ordered child support, Wisconsin provides several enforcement mechanisms. The Wisconsin Department of Children and Families reports that it collects billions of dollars in child support each year, but many families still struggle with non-payment issues.

Enforcement options available in Wisconsin include:

• Income withholding that automatically deducts support from paychecks

• Interception of state and federal tax refunds

• Suspension of driver's licenses, professional licenses, and recreational licenses

• Liens against real estate and personal property

• Reporting delinquent payments to credit bureaus

• Contempt of court proceedings that can result in fines or jail time

• Denial or revocation of passports for parents who owe substantial arrears

The custodial parent can work with the Wisconsin Child Support Program or hire a private attorney to try to get unpaid child support. In serious cases of non-payment, the non-paying parent may face criminal charges.

Call a Milwaukee, WI Family Lawyer Today

Establishing and enforcing child support orders when parents are unmarried requires navigating complex legal procedures and understanding Wisconsin's specific guidelines.

At Gimbel, Reilly, Guerin & Brown, LLP, we give our clients effective legal representation to help them deal with child support and other family law matters. Our Milwaukee child support attorneys understand how to protect your rights and ensure your children receive the support they need. Contact us at 414-271-1440 today to schedule a free consultation.