Child Support Guides
15 source-linked guides to the numbers and the decisions a calculator cannot make: income, parenting time, support ending, college costs and missed payments. State comparisons identify their limited coverage and link the official rules. Use the connected tools only within their stated calculation scope.
Reviewed by SupportDecode Editorial Team Page content reviewed Sources Methodology Update log
Prepare for a child support review
A private, printable document checklist separates court modification from agency review in five researched states. No score or eligibility prediction.
Open the modification preparation checklistHow the math works
The moving parts inside every guideline formula: the model, the income base, and what counts.
- The three support modelsIncome shares, percentage of income, and Melson: how each works and who uses which.Read the guide
- Gross vs net incomeTexas tax charts, Georgia gross pay, Illinois conversion tables: why the base differs.Read the guide
- What counts as incomeOvertime, bonuses, self-employment, and the imputed income concept, state by state.Read the guide
Parenting time and support
How schedules are written and how the overnight math feeds the support formulas.
- 50/50 custody and supportThresholds, offsets, and the one state that ignores equal time entirely.Read the guide
- Reading a custody scheduleCycles, overnight counts, and why the advertised split is not always the real one.Read the guide
- Moving with a childCalifornia, Illinois and Texas: notice, geographic restrictions and court review.Read the guide
- A child’s custody preferenceBeing heard is not choosing: California, Texas and Illinois participation rules.Read the guide
When payments are missed
What happens to unpaid support: interest rules and the limits on paycheck withholding.
- Interest on arrearsSimple, compound, or none: how unpaid support grows and when judgments matter.Read the guide
- Garnishment limitsThe federal 50/55/60/65 matrix, disposable earnings, and the states that cap lower.Read the guide
- Passport and license holdsFederal passport certification and selected state license notice, payment and release rules.Read the guide
Alimony, taxes, and changes over time
The obligations that sit next to child support, and how orders get revisited.
- Alimony and child supportWhich is computed first, how one changes the other, and the post-2019 tax rules.Read the guide
- The child tax creditThe 2026 $2,200 credit, Form 8332 mechanics, and what alternating years is worth.Read the guide
- When support can changeThe substantial-change concept, guideline refresh cycles, and the no-retroactivity rule.Read the guide
- When child support endsFive selected states: school, dependency, order terms, arrears and withholding.Read the guide
- College costs after divorceIllinois, Massachusetts and New York education awards, aid and existing support.Read the guide
How these guides are sourced
Every consequential figure in these guides traces to an official statute, court rule, or agency publication in the source list at the bottom of each page, with the date we last verified it. Where a fact could not be verified against an official source, it was left out. The guides explain concepts; they do not give legal advice, and the calculators they link always show their own effective dates and sources.
Changelog: guides library expanded on and now lists 15 source-linked guides. Material changes are dated in the update log.