7 Child Support Mistakes That Will Destroy Your Illinois Case

Published: 3/22/2026
By Jonathan D. Steele
7 Child Support Mistakes That Will Destroy Your Illinois Case

What should you know about 7 child support mistakes that will destroy your illinois case?

Quick Answer: Case Summary: In re Marriage of Siddiqui, 2025 IL App (3d) 220355-U - A single undocumented overnight count or a $350 discrepancy in insurance costs can transform a straightforward Illinois child support case into a $100,000 appellate disaster, as the Third District's reversal in *In re Marriage of Siddiqui* starkly demonstrates. From inaccurate parenting time records and inconsistent financial affidavits to deleted text messages and social media missteps, these seven preventable mistakes cost parents custody, credibility, and tens of thousands in legal fees—making meticulous documentation and strategic restraint essential survival tools in family court.
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Frequently Asked Questions

How is child support calculated in Illinois?

Illinois uses the income shares model under 750 ILCS 5/505. Both parents' net incomes are combined, a basic support obligation is determined from statutory guidelines, and each parent pays their proportionate share. Adjustments apply for parenting time exceeding 146 overnights (40%).

What income counts for Illinois child support calculations?

Net income includes salary, wages, bonuses, commissions, self-employment income, rental income, and most other earnings. Courts can impute income if a parent is voluntarily unemployed or underemployed. Certain expenses like health insurance premiums and prior support obligations are deducted.

When can child support be modified in Illinois?

Under 750 ILCS 5/510, modification requires a substantial change in circumstances. Examples include 20%+ income change, job loss, disability, or significant changes in the child's needs. Support automatically continues until age 18 (or 19 if still in high school).

Jonathan D. Steele

Written by Jonathan D. Steele

Chicago divorce attorney with cybersecurity certifications (Security+, ISC2 CC, Google Cybersecurity Professional Certificate). Illinois Super Lawyers Rising Star 2016-2025.

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