California child support guidelines

California uses an income-shares guideline — a formula built on both parents’ net incomes and parenting time. This page explains how it works and links California’s official Guideline Calculator; it doesn’t compute your amount.

How the California formula works

California’s statutory formula (Family Code § 4055) is CS = K[HN − (H%)(TN)], which looks at:

• Both parents’ net disposable incomes — not just the paying parent’s;
• Timeshare — the percentage of time the child spends with each parent, which directly changes the result;
• The high earner’s share of the combined income;
• Mandatory add-ons — health insurance and work-related childcare, split between the parents.

Because it’s an actual algebraic formula rather than a flat percentage, the same salary can produce very different results depending on timeshare and the other parent’s income — which is exactly why California publishes an official Guideline Calculator instead of a lookup table. Notably, California applies the formula at all income levels (there is no statutory income cap the way New York and Florida have one).

The 2024 overhaul and the low-income adjustment

Senate Bill 343, effective September 1, 2024, revised the guideline formula for the first time in decades and reworked the low-income adjustment. A parent whose net income is below about $2,929 a month (2026) gets a rebuttable presumption of a reduced obligation, and that threshold is now tied to the state minimum wage and updated annually — so low-income orders can shift each year even if nothing else changes.

How long support lasts, and changing it

California support runs until the child turns 18, or 19 if they’re still a full-time high-school student living at home (longer for a child who can’t support themselves). An order can be modified on a substantial change in circumstances — an income swing, a timeshare change, disability, incarceration, or a new child. If a parent has voluntarily lowered their income, a court can impute income based on earning capacity.

Use the official calculator

The California Department of Child Support Services provides the official Guideline Calculator (linked above) — it applies the same formula, timeshare inputs, and low-income adjustment the courts use. Use it for an estimate; this page only explains the model.

For a real case

The guideline amount is presumed correct but can be adjusted in limited circumstances the law allows. For advice on your situation, consult a California family-law attorney.