How Child Support Is Awarded in IL Based on Parenting Time and Income Differences

Child support is one of the most significant issues parents face when divorcing, separating, or establishing parentage in Illinois. The amount ordered by the court affects both your financial stability and your child’s well-being. You may be concerned about how support is calculated, how parenting time affects the numbers, or whether the difference between your income and the other parent’s income will influence the final result.

Illinois law provides a detailed framework for determining child support. The primary controlling statute is 750 ILCS 5/505, which outlines the state’s Income Shares Model, how courts define net income, when parenting time affects support, and when courts may deviate from standard guidelines. Parenting time is determined under 750 ILCS 5/602.7, and modifications of support are addressed in 750 ILCS 5/510. Together, these provisions dictate how child support is awarded, enforced, and modified.

Below, Collin Law Offices, P.C. explains how child support is calculated under Illinois law, how parenting time affects the result, how income disparity influences who pays and how much, and when courts may order non-guideline support.

How the Income Shares Model Works Under 750 ILCS 5/505

Illinois uses the Income Shares Model, established in 750 ILCS 5/505(a), to calculate support. The model is designed to approximate what parents at a given combined income level would spend on their child if they still lived together. It attempts to ensure that children enjoy a comparable standard of living in both households.

Under the statute, the court must:

1. Determine each parent’s gross income.

2. Convert gross income to net income using either the standardized or individualized tax method described in the statute.

3. Combine both parents’ net incomes to calculate combined net income.

4. Reference the statutory Schedule of Basic Child Support Obligations to identify the amount allocated for the number of children.

5. Allocate that amount between parents based on their respective percentages of combined net income.

6. Adjust the amount according to parenting time if applicable.

Courts must apply this guideline calculation unless one party proves that following the guidelines would be “inequitable, unjust, or inappropriate,” as permitted under 750 ILCS 5/505(a)(2).

How Illinois Defines Gross Income for Child Support Purposes

Under 750 ILCS 5/505(a)(3), “gross income” includes income “from all sources,” with limited statutory exclusions. The statute is intentionally broad to prevent manipulation of income and ensure a realistic assessment of a parent’s financial ability.

Examples of income that typically fall under the statutory definition include:

• Wages or salary from employment

• Overtime, bonuses, commissions, and incentives

• Self-employment income and business profits

• Rental income

• Severance pay

• Certain pension or retirement payments

• Disability benefits (if not means-tested)

• Income from investments or recurring payments

Income excluded under the statute includes means-tested public benefits, child support received for children not involved in the case, and certain disability payments intended for a different child.

Because of this broad definition, courts frequently look beyond tax returns and consider whether reported income reflects actual financial resources. If a parent reduces income voluntarily or manipulates deductions, the court may apply imputed income under 750 ILCS 5/505(a)(3.3).

How Net Income Is Calculated Under 750 ILCS 5/505

Net income is not simply “take-home pay.” Illinois provides two methods for calculating net income: the standardized tax amount method and the individualized tax amount method.

Standardized Tax Amount Method

This is the default method under 750 ILCS 5/505(a)(3.1). The statute provides standardized tax amounts that approximate federal income tax, state income tax, Social Security, and Medicare. These standardized amounts are subtracted from gross income to calculate net income.

This method creates consistency between cases and reduces conflict over tax deductions.

Individualized Tax Amount Method

Under 750 ILCS 5/505(a)(3.2), either parent may request individualized net income if their tax situation warrants it. This method uses actual tax liabilities, deductions, and withholding amounts.

This may be appropriate for self-employed parents, parents with multiple dependents, or parents who have substantial variations in income throughout the year.

Choosing between these methods may significantly impact the final child support amount, and courts must make findings when granting or denying such a request.

Determining the Basic Child Support Obligation

Once each parent’s net income is calculated and combined, the court locates the Basic Child Support Obligation on the statutory schedule adopted under 750 ILCS 5/505(a)(1.5). The schedule lists the estimated monthly cost of raising children at different combined income levels.

The court allocates that obligation between parents proportionally. For example, if Parent A earns 70% of the combined net income and Parent B earns 30%, Parent A is responsible for 70% of the basic child support obligation.

If Parent B has the majority of parenting time and Parent A has fewer than 146 overnights, Parent A generally pays their percentage share to Parent B under 750 ILCS 5/505(a)(1.5).

When the combined net income exceeds the schedule’s highest value, 750 ILCS 5/505(a)(3.5) gives the court discretion to set a reasonable amount while using the highest schedule amount as a minimum.

Parenting Time and the 146-Overnight Threshold Under Illinois Law

Parenting time is governed by 750 ILCS 5/602.7, which outlines how courts allocate overnights based on the child’s best interests. Parenting time directly affects child support only when both parents have at least 146 overnights per year. This threshold is established in 750 ILCS 5/505(a)(3.8), which governs “shared parenting” situations.

When Parenting Time Does Not Change the Formula

If one parent has fewer than 146 overnights, the shared parenting formula does not apply. Instead, the parent with fewer than 146 overnights generally pays their guideline share of support to the parent with more overnights. In these cases, child support is based primarily on income, not parenting time.

When Parenting Time Does Change the Formula (Shared Parenting)

If both parents have at least 146 overnights, the shared parenting formula under 750 ILCS 5/505(a)(3.8) applies. This calculation involves:

1. Increasing the Basic Child Support Obligation by 50% to account for duplicated household expenses.

2. Allocating the increased obligation between the parents proportionally.

3. Adjusting each parent’s allocated share based on the percentage of time the child spends with the other parent.

4. Offsetting the obligations, with the parent owing the higher adjusted amount paying the difference.

Why High Parenting Time Does Not Eliminate Support

Even when parents share time equally (or close to equally), child support may still be ordered—especially when there is a significant income difference. This is because the shared formula is income-based, not time-based. The higher-earning parent almost always owes support so that the child’s standard of living remains consistent in both homes.

How Income Disparity Influences Child Support in Illinois

Income disparity is one of the most influential factors in Illinois child support cases. The Income Shares Model is designed to ensure that children benefit proportionally from each parent’s financial resources. For this reason, large income gaps often mean the higher-earning parent will owe support, even with substantial parenting time.

Examples of scenarios highly influenced by income disparity include:

• A 50/50 parenting schedule where one parent earns considerably more

• Cases involving self-employment or business ownership

• Situations where one parent receives bonuses or fluctuating additional income

• Cases involving voluntarily reduced income or underemployment, which may trigger imputed income under 750 ILCS 5/505(a)(3.3)

• Situations where one parent has minimal income due to childcare duties or limited earning capacity

Illinois law makes clear that parenting time does not override income disparity. The goal is to ensure financial stability for the child, not equalize expenses between parents.

When Courts Deviate From Guideline Child Support

Under 750 ILCS 5/505(a)(2), courts may deviate from the statutory guidelines when the guideline amount would be “inequitable, unjust, or inappropriate.” Any deviation must include written findings explaining why the guideline amount was not used.

Circumstances that may justify deviation include:

• Extraordinary medical expenses

• Special educational or developmental needs

• Costs associated with long-distance parenting time

• The financial resources and needs of the child

• A parent’s extraordinary income or unusual financial circumstances

Deviation is not the norm, but Illinois courts retain flexibility to account for unique circumstances.

Modification of Child Support Orders Under 750 ILCS 5/510

Child support orders may be modified when there is a substantial change in circumstances. Under 750 ILCS 5/510(a), common reasons for modification include:

• A significant change in either parent’s income

• A change in the parenting time schedule

• A child’s evolving medical or educational needs

• A parent becoming unemployed or underemployed

• Large shifts in health insurance or childcare costs

Modifications are effective only from the date a petition is filed, not the date circumstances changed, which makes timely action crucial.

Documents Parents Should Gather for a Child Support Case

Whether establishing or modifying support, parents should prepare by gathering relevant documentation. Useful records include:

• Recent pay stubs and tax returns

• Documentation of bonuses or commissions

• Business records for self-employed parents

• Proof of child-related expenses

• Health insurance and childcare cost information

Proper preparation ensures an accurate and fair calculation under the statutory guidelines.

Common Misunderstandings About Illinois Child Support

Several misconceptions frequently arise in child support cases:

• Equal parenting time does not eliminate child support. Income still controls the outcome.

• Child support does not automatically include extracurricular or extraordinary expenses unless ordered by the court under 750 ILCS 5/505.2.

• Self-employment does not allow a parent to hide income; courts can impute income under 750 ILCS 5/505(a)(3.3).

• The guideline number is not always final; deviation is allowed when justified.

• Support is modifiable, but only prospectively from the date a petition is filed under 750 ILCS 5/510.

Understanding these limitations helps you prepare for a realistic outcome.

Chicago Child Support Lawyer

If you are facing a child support issue in Illinois—whether initial establishment, modification, enforcement, or a dispute involving parenting time or income differences—you should speak with an experienced family law attorney. Child support calculations involve specific statutory requirements under 750 ILCS 5/505, and even small changes in income or parenting time can dramatically alter the final amount.

The child support attorneys at Collin Law Offices, P.C. can evaluate your income, parenting schedule, and financial circumstances to determine the likely outcome of your case and advocate for your rights under Illinois law.

To understand your options and protect your interests, contact Collin Law Offices, P.C. by calling (312) 263-1252 or contacting us online for a free consultation.