FAMILY LAW CALCULATORS

Child Support Modification Calculator — United States

Estimate how monthly child support will change when income increases or decreases under US state guidelines.

$
Payor's current gross annual income as per existing order.
$
Payor's new gross annual income after the change.

Enter your details to see results

Disclaimer: Uses simplified income-share estimates. Actual child support depends on your state's specific formula, deductions, and childcare add-ons. Consult a family law attorney.

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Frequently Asked Questions

When can child support be modified in the US?
Most states require a 'substantial change in circumstances' to modify child support — typically a 10–15%+ change in income, job loss, disability, or a significant change in the child's needs or custody arrangement. Some states allow automatic review every 3 years regardless of a change. File a motion to modify in the court that issued the original order.
Can child support be reduced if I lose my job?
Yes. Job loss is a classic change in circumstances warranting modification. However, courts evaluate whether the job loss was voluntary. If you quit or were fired for cause, the court may impute income based on your earning capacity. File for modification immediately — courts generally cannot reduce child support retroactively before the date you filed the motion.
How long does it take to modify a child support order?
An uncontested modification by agreement can be done in 4–8 weeks. A contested modification requires a court hearing and typically takes 3–6 months. Some states offer administrative modification (through the child support agency) which can be faster. Do not simply stop paying the current order while waiting — arrears accrue regardless.

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