Free estimate · California
California Child Support Calculator
A free estimate under California's guidelines, with the math shown line by line.
- Guideline model
- Algebraic statewide uniform guideline using net disposable income and parenting-time share
- Effective
- 1992-07-01 (formula; current statutes and 2026 tax/minimum-wage inputs apply)
- Source
- Family Code § 4055
This is an estimate for information only — not legal advice, and not a court calculation. Judges can and do deviate from guideline amounts. For the number a court would use, see California Family Code §4055.
This number is a snapshot. Child support depends on parenting time, and parenting time drifts — swapped weekends, changed holidays, summer schedules. Vireo keeps the custody calendar, messages and shared expenses in one timestamped record, so what actually happened is never a matter of memory.
See what Vireo tracks →How California calculates child support
CS = K[HN − (H% × TN)], where CS is child support; K is the fraction of combined income allocated to support under § 4055(b)(3); HN is the high earner's monthly net disposable income; H% is the approximate percentage of time the high earner has or will have primary physical responsibility for the children; and TN is both parents' total monthly net disposable income. Multi-child multipliers and special rules in § 4055 apply.
How income is counted: Annual gross income is defined by Family Code § 4058. Monthly net disposable income is gross income reduced by deductions allowed by § 4059, including actual federal and state tax liability, FICA or equivalent, mandatory retirement and union dues, health premiums, state disability premiums, qualifying support payments, and permitted hardship deductions. Tax calculations and filing-status assumptions are integral.
Source: Family Code § 4055 · Effective 1992-07-01 (formula; current statutes and 2026 tax/minimum-wage inputs apply)
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