Imputing Income for Child Support in Illinois

When an Illinois court calculates child support, it bases the amount on each parent’s actual income. But what happens when a parent is voluntarily unemployed, deliberately underemployed, or hiding income to reduce their support obligation? In those situations, the court can impute income — assigning an earning capacity to that parent based on what they could reasonably be earning, rather than what they claim to earn.

Imputing income is one of the most contested issues in Illinois child support cases. Under 750 ILCS 5/505, the court has broad authority to look beyond a parent’s reported income and determine what they are capable of earning. This article explains when Illinois courts impute income, how they calculate it, what evidence matters, and how self-employment and other special circumstances affect the analysis.

When Courts Impute Income

Illinois courts impute income when a parent is not earning what they could reasonably be expected to earn, and the shortfall appears to be voluntary or intentional. The most common scenarios include:

Voluntary unemployment. A parent quits their job, refuses to seek employment, or takes extended time off without a legitimate reason. If a parent with a professional degree and a history of earning $120,000 per year suddenly stops working, the court will not simply accept zero income for child support purposes.

Voluntary underemployment. A parent takes a job that pays significantly less than what they are qualified to earn. An accountant who leaves a full-time position to work part-time at a retail store may face imputed income based on their accounting credentials and employment history.

Deliberate income reduction. A parent intentionally reduces their income in anticipation of a child support proceeding. This can include declining promotions, reducing work hours, or restructuring a business to minimize reported income.

Failure to seek employment. A parent who is capable of working but makes no genuine effort to find a job may have income imputed. Courts expect parents to actively pursue employment, especially when child support is at issue.

How Illinois Calculates Imputed Income

Illinois does not have a single formula for imputing income, but courts follow a consistent analytical framework.

Step 1: Determine Whether Imputation Is Appropriate

The court first considers whether the parent is voluntarily unemployed or underemployed. This requires examining:

• The parent’s employment history over the past several years
• The circumstances surrounding any job loss or income reduction
• Whether the parent has made good-faith efforts to find employment
• Whether there is a legitimate reason for reduced earnings (such as a documented disability, caring for a child with special needs, or a bona fide career change)

Step 2: Assess Earning Capacity

If the court determines that imputation is warranted, it calculates the parent’s earning capacity based on:

• Education and training. Degrees, certifications, licenses, and specialized skills the parent holds.
• Recent employment history. What the parent has earned in recent years provides the strongest evidence of what they can earn now.
• Job market conditions. The availability of jobs in the parent’s field and geographic area.
• Age and health. Physical or mental limitations that genuinely affect the parent’s ability to work.
• Childcare responsibilities. If the parent is the primary caretaker of young children, the court considers whether full-time employment is realistic.

Step 3: Apply the Imputed Income to the Support Formula

Once the court determines an earning capacity, it plugs that number into the Illinois income shares child support formula as if the parent were actually earning that amount. The resulting support obligation is based on imputed income rather than actual income.

The Illinois Income Shares Model

Understanding imputed income requires a basic knowledge of how Illinois calculates child support. Since 2017, Illinois has used the income shares model under 750 ILCS 5/505, which considers both parents’ incomes.

The basic steps are:

1. Determine each parent’s net income
2. Combine both incomes to find the total family income
3. Use the statutory guidelines table to find the basic child support obligation based on the combined income and number of children
4. Allocate the obligation proportionally based on each parent’s share of the combined income
5. Apply adjustments for parenting time, health insurance, childcare costs, and other factors

When income is imputed to one parent, it raises that parent’s share of the combined income, which increases their proportional responsibility for child support. For a broader overview of child support calculations, see our guide on how child support is calculated.

Evidence Courts Consider

If you are seeking to impute income to the other parent — or defending against imputation — the evidence you present is critical.

Evidence supporting imputation:

• The parent’s resume, LinkedIn profile, and professional credentials
• Tax returns and W-2s from the past three to five years showing prior earnings
• Evidence of job offers declined or promotions refused
• Testimony from vocational experts regarding the parent’s earning capacity in the current job market
• Evidence that the parent’s lifestyle (housing, vehicles, travel) is inconsistent with their reported income
• Records showing the parent stopped working or reduced hours shortly before or after the support case was filed

Evidence against imputation:

• Medical records documenting a disability or health condition that limits work capacity
• Evidence of a genuine job search, including applications submitted, interviews attended, and responses received
• Documentation of a legitimate reason for a career change or reduced hours, such as returning to school
• Evidence that the parent is the primary caretaker of a young child or a child with special needs
• Testimony from employers or industry professionals regarding job market conditions

Self-Employment and Imputed Income

Self-employment creates unique challenges in imputed income cases. Self-employed parents have more control over their reported income, which can make it difficult to determine actual earnings.

Illinois courts address this by examining:

• Business tax returns and financial statements for the past several years
• Business expenses claimed — courts scrutinize deductions that reduce reported income, particularly personal expenses run through the business (vehicles, meals, travel, cell phones)
• Cash-based income — in businesses that deal heavily in cash, courts may look at lifestyle evidence, bank deposits, and third-party records to assess actual income
• Business growth or decline — whether changes in reported income correlate with legitimate business conditions or with the timing of the support case

A self-employed parent who reports $40,000 in income but lives in a $600,000 home, drives a luxury vehicle, and takes multiple vacations per year will face scrutiny. The court can impute income based on the evidence of actual spending that exceeds reported earnings.

Deviation Factors

Even after imputing income, the court retains discretion to deviate from the guideline child support amount. Under 750 ILCS 5/505, deviation factors include:

• The financial resources and needs of the child
• The financial resources and needs of both parents
• The standard of living the child would have enjoyed if the parents had remained together
• The physical, mental, and emotional needs of the child
• Educational expenses

A deviation can result in a higher or lower support amount than the guidelines suggest. The court must explain its reasoning for any deviation on the record.

What to Do Next

If imputed income is an issue in your Illinois child support case, consider these steps:

1. Gather financial records. Collect tax returns, pay stubs, bank statements, and any evidence of the other parent’s income, assets, and lifestyle.
2. Document employment history. Build a timeline of the other parent’s jobs, earnings, and any changes that coincided with the support case.
3. Consider a vocational expert. In complex cases, a vocational expert can testify about the parent’s earning capacity based on their skills, education, and the local job market.
4. If you are defending against imputation, document everything. Keep records of your job search, medical conditions, or other reasons for reduced income. Show the court that your situation is genuine.
5. Consult an Illinois family law attorney. Imputing income involves complex factual analysis and significant judicial discretion. Schedule a consultation with an attorney experienced in Illinois child support cases to evaluate your situation and develop a strategy.

Frequently Asked Questions

When will an Illinois court impute income?

Illinois courts impute income under 750 ILCS 5/505 when a parent is voluntarily unemployed, voluntarily underemployed, deliberately reducing income in anticipation of a support proceeding, or failing to seek employment without legitimate cause. The critical question is whether the income reduction is voluntary and without good cause. A parent who lost their job in a layoff or stays home to care for a very young child has a legitimate reason.

How does Illinois calculate imputed income?

Courts follow a three-step process: first, determine whether imputation is appropriate by examining employment history and the circumstances of any income reduction. Second, assess earning capacity based on education, training, recent earnings history, job market conditions, age, and health. Third, plug the imputed income into the Illinois income shares formula (both parents’ net incomes, combined, guideline table, proportional allocation).

What evidence is most effective in an imputation case?

If seeking imputation: gather the other parent’s resume and LinkedIn profile, 3-5 years of tax returns showing prior earnings, evidence of declined job offers, and testimony from vocational experts. If defending against imputation: document your job search with applications and responses, provide medical records for health limitations, or show enrollment in education programs that will increase future earning capacity.

How does self-employment complicate imputed income in Illinois?

Self-employed parents have more control over reported income. Courts examine business tax returns, scrutinize personal expenses claimed as business deductions, compare lifestyle evidence against reported income, and analyze whether changes in reported income correlate with the timing of the support case. A parent reporting $40,000 in income while living in a $600,000 home will face scrutiny.

How This Guide Was Researched

This guide was created by reviewing publicly available legal information from official state statutes, judiciary websites, court resources, and family law publications. The goal is to explain family law topics in plain English so readers can better understand the process before speaking with an attorney.

Sources and Legal References

This guide is based on publicly available legal information and official sources, including:

• Illinois state statutes and family law codes
• Illinois judicial branch website and court resources
• Official Illinois court forms and filing instructions
• Illinois child support guideline publications
• State bar association and legal aid resources

Official Illinois Resources

• Illinois Courts – Self-Help
• Illinois Divorce, Child Support & Maintenance Forms

For more about how we research our guides, see our editorial policy and sources methodology.

Related Guides

Learn more about related family law topics:

• Child custody laws explained
• Child support enforcement
• Property division in divorce
• How child support is calculated
• How alimony works
• Child support calculator
• 50/50 custody

Last updated: March 2026. This guide summarizes general legal information based on publicly available sources and is provided for educational purposes only. It does not constitute legal advice. For advice specific to your situation, consult a licensed attorney in your state.