Child Support Guides
The calculators answer the number. These guides answer the questions around it: what an order adds on top, what parenting time actually changes, and how income is measured when it is not a salary.
Updated November 12, 2026 Sources and methodology
- Child support add-ons Childcare, health insurance, dental, and uninsured costs: how they are ordered on top of basic support and how they are split.
- 50/50 custody and child support Why equal time rarely means zero, the four mechanisms states use, and what counts as an overnight.
- Variable income child support Self-employment, overtime, bonuses, and commissions: what counts as income and which monthly figure to enter.
- How to modify a support order Nothing changes on its own: what counts as a substantial change, the agency and court routes, and why the filing date matters.
- Child support arrears How unpaid support accrues, whether interest applies, how it is collected, and what to check in the balance.
Where to start
If your order already exists and the amount looks low, start with the add-ons guide: childcare, the child’s health insurance, and uninsured costs are usually ordered on top of the basic number. If you share time close to equally, read the 50/50 guide before assuming support goes to zero. If your pay is not a fixed salary, the variable-income guide explains which monthly figure to enter so the estimate is not built on a single unusual month. If the facts changed and the order did not, the modification guide explains why the filing date matters more than the reason.
Every guide links back to the twenty state calculators, and each state page cites the statute or schedule that the estimate applies.