Child Support State Guideline Calculator

How do states calculate the base child support amount?

States typically calculate the base child support amount by applying specific mathematical formulas outlined in their state guidelines. Most states use one of three primary models:

1. Income Shares Model: Calculates support based on the combined income of both parents, estimating what would have been spent on the child if the family remained intact.
2. Percentage of Income Model: Bases the support amount strictly on a set percentage of the non-custodial parent's income.
3. Melson Formula: A more complex variation of the Income Shares model that applies a "self-support reserve" to ensure parents' basic needs are met before calculating child support.

What specific income sources are included in the calculation?

Most states take a broad approach to calculating gross income for child support. Below is a breakdown of common income sources:

How does shared parenting time affect the final support order?

In most jurisdictions, the amount of overnight visits or the percentage of shared parenting time directly impacts the final support obligation. As the non-custodial parent's parenting time increases, their child support payment generally decreases. This reduction is designed to reflect the direct, day-to-day costs (like food, electricity, and transportation) that the non-custodial parent assumes while the child is in their physical care.

Under what circumstances can a judge deviate from the guidelines?

Judges presume that state guideline calculations are correct, but they can order a deviation if applying the formula would be unjust or inappropriate. Circumstances justifying a deviation often include:

• Extraordinary medical, psychological, or educational needs of the child.
• Unusually high travel costs associated with parenting time/visitation.
• Extreme financial hardship of a parent (e.g., mandatory union dues, high debt from the marriage).
• The child possesses a substantial independent source of income.

Are childcare and health insurance costs factored into the base amount?

Generally, childcare and health insurance premiums are not included in the basic child support figure, which is meant to cover ordinary expenses like food, shelter, and clothing. Instead, work-related childcare and health insurance costs are considered "mandatory add-ons." The court determines the total cost of these expenses and divides them between the parents, usually proportional to their respective incomes, adding the paying parent's share to the base support amount.

What qualifies as a substantial change to justify modifying the support?

To modify an existing child support order, a parent must prove a "substantial and continuing change in circumstances." Most states define this as a change that would alter the current support order by a specific threshold (e.g., 10% to 15%). Qualifying changes include:

• Involuntary job loss or a significant change in income.
• A permanent disability or severe illness of a parent.
• A major shift in physical custody or parenting time.
• Significant changes in the child's needs, such as a new medical diagnosis.

How does the state handle voluntarily unemployed or underemployed parents?

If a court determines that a parent has intentionally quit their job, taken a lower-paying role, or refused to work to avoid paying child support, the judge may "impute" income. This means the court calculates the child support obligation based on the parent's earning capacity rather than their actual current income. Judges assess the parent's work history, educational background, skills, and the local job market to determine this imputed figure.

Does the model use combined parental income or just the paying parent's income?

This depends entirely on the guideline model adopted by the specific state:

• Combined Income: The vast majority of states (over 40) use the Income Shares Model or the Melson Formula, which pools the gross income of both parents to determine the total child support obligation before dividing it.
• Paying Parent's Income: A minority of states use the Percentage of Income Model, which calculates the support amount using only the gross or net income of the non-custodial (paying) parent, regardless of what the custodial parent earns.

At what age or life event does the child support obligation legally terminate?

Child support obligations typically terminate when the child reaches the age of majority, which is 18 in most states, but 19 or 21 in a few others. Other terminating life events, known as emancipation, include the child getting married, joining the active-duty military, or becoming entirely self-supporting. Exceptions exist; courts may order continued support past the age of majority if the child has a severe disability, or if the parents agreed to fund college expenses.

How are out-of-pocket medical and educational expenses divided between parents?

Unreimbursed, out-of-pocket medical expenses (such as copays, deductibles, braces, or therapy) and agreed-upon educational expenses (such as private school tuition or specialized tutoring) are typically divided proportionally based on the parents' relative incomes. For instance, if one parent earns 60% of the combined household income and the other earns 40%, they will split these extra out-of-pocket costs at a 60/40 ratio. Usually, one parent pays upfront and submits receipts to the other for reimbursement.

Sources:

• NCSL: Child Support Guideline Models
• Nolo: Child Support Basics
• ACF: Child Support Basics

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