California Child Support Calculator
California uses a statewide uniform guideline formula, presumed correct unless a statutory ground for deviation is proved.
Formula — CS = K[HN − (H%)(TN)]
HN = high earner's net monthly disposable income; TN = both parents' combined net monthly disposable income; H% = the share of time the high earner has primary physical responsibility. K = (1 + H%) if H% is 50% or less, or (2 − H%) if H% is over 50%, multiplied by the income fraction from the table below. If the result is positive, the high earner pays it; if negative, the low earner pays its absolute value.
| Total net income (TN) | Income fraction |
|---|---|
| $0–$2,900 | 0.165 + TN/82,857 |
| $2,901–$5,000 | 0.131 + TN/42,149 |
| $5,001–$10,000 | 0.250 |
| $10,001–$15,000 | 0.10 + 1,499/TN |
| Over $15,000 | 0.12 + 1,200/TN |
This is the K-table operative from 1 September 2024. Older K-tables circulating online are superseded and are not used here.
Multi-child multipliers
The 1-child result is multiplied by 1.6 (2 children), 2.0 (3), 2.3 (4), 2.5 (5), 2.625 (6), 2.75 (7), 2.813 (8), 2.844 (9), 2.86 (10).
Net disposable income (§4059)
Gross income minus only: state/federal taxes actually owed; FICA (or equivalent); mandatory union dues and mandatory retirement required as a condition of employment (voluntary 401(k) does not count); health-insurance premiums for the parent and children they must support, plus state disability insurance; support actually paid under a court order for a non-subject person; court-allowed job-related expenses; and hardship deductions. Personal living costs do not count.
Add-ons (§§4061–4063, current rule from 1 September 2024)
Mandatory add-ons: childcare actually incurred for employment or reasonably necessary education/training, and reasonable uninsured health-care costs. Discretionary: educational/special-needs costs and visitation travel. Split rule: add-on expenses are divided in proportion to the parents' net incomes as adjusted by §4061(c)–(d) — spousal support adjusts gross income while it is in effect and paid, and the child-support payor's net is reduced by the basic support ordered — unless a party requests or the court finds a different manner. An older half-and-half default was the pre-September-2024 law and is not the current rule.
Caps, low income, custody
There is no dollar cap and no fixed high-income threshold in the statute. Deviation for “extraordinarily high income” is available where the formula would exceed the children's needs, but that phrase has no dollar definition — none is invented here. A low-income adjustment may reduce support where the obligor's net disposable income is below full-time minimum-wage gross. Custody is continuous: H% enters the formula directly, so every point of time changes the result — there is no overnight cliff.
Worked example
HN $6,000, low earner $2,000, TN $8,000, H% 20%, 1 child, no add-ons. TN $8,000 → fraction 0.250. K = (1 + 0.20) × 0.250 = 0.30. CS = 0.30 × [$6,000 − (0.20 × $8,000)] = 0.30 × $4,400 = $1,320/month. At 50% timeshare the same inputs give $750/month; for 2 children the $1,320 figure becomes $2,112/month before add-ons.
End of support
For an unmarried child who has turned 18, is a full-time high-school student and is not self-supporting: until 12th-grade completion or age 19, whichever comes first. Parents may agree to more.
Sources: California Family Code §§4055, 4057, 4059, 4061, 3901. §4055 · §4061
How to use this calculator
Enter net monthly disposable income, not gross pay. California net disposable income is gross income minus only the deductions in Family Code §4059 — taxes actually owed, FICA, mandatory union dues and mandatory retirement, health-insurance premiums, support actually paid for a non-subject person, allowed job expenses and hardship deductions. Voluntary 401(k) contributions do not reduce it. Enter H% as the high earner's share of primary physical responsibility, averaged across children if timeshares differ. If the result is negative, the low earner pays its absolute value — the calculator states who pays.
Additional worked examples
| High / low earner net income | H% / children | Calculation | Result |
|---|---|---|---|
| $4,000 / $1,000 | 30% / 2 | TN $5,000, fraction ≈ 0.2496, K ≈ 0.3245; 0.3245 × ($4,000 − $1,500) × 1.6 | About $1,298/month, high earner pays |
| $10,000 / $0 | 50% / 1 | TN $10,000, fraction 0.250, K 0.375; 0.375 × ($10,000 − $5,000) | $1,875/month, high earner pays |
| $3,000 / $3,000 | 80% / 1 | TN $6,000, fraction 0.250, K 0.30; 0.30 × ($3,000 − $4,800) = −$540 | $540/month, low earner pays (absolute value) |
The third example is instructive: when the high earner has most of the time, the formula can reverse who pays. That is not an error — it follows from H% entering the formula directly.
Common mistakes
- Using gross income. California's formula runs on net disposable income under §4059. Gross-income inputs overstate support.
- Using an old K-table. Tables circulating online from before 1 September 2024 are superseded. This page uses only the September 2024 table.
- Splitting add-ons 50/50. Since 1 September 2024, §4062 expenses are divided in proportion to adjusted net disposable incomes under §4061, unless the court orders otherwise. The old equal-split rule must not be used.
- Inventing a high-income threshold. California has no dollar cap and no fixed “extraordinarily high income” threshold. Deviation on that ground is a court finding, not a number in a calculator.
- Treating timeshare as a cliff. California has no overnight threshold. Every point of H% changes the result, unlike Illinois, which uses a threshold.
How courts deviate from the guideline
A guideline figure is a presumption, not a guarantee. Courts commonly depart where the guideline would be unjust or inappropriate on the facts: a child's proven needs or special expenses, a parent's other obligations, hardship, high or very low income, shared-care arrangements that change real costs, and tax or benefit effects the formula does not capture. Where a court deviates, it generally must explain why and state the guideline figure it departed from. That is why every calculator on this site shows its formula and its cap: you can see what the court starts from, even if the final order differs.
Deviation grounds in §4057 include a stipulation, a deferred sale of the family residence, non-contribution commensurate with custodial time, the low-income adjustment, and special circumstances. A court that deviates must state its reasons on the record.
When to hire a lawyer
An estimate is a starting point, not a strategy. Talk to a licensed attorney in the relevant jurisdiction before you rely on a figure if any of these apply: custody is disputed; there is a business, professional practice or complex property to value; retirement accounts, stock or deferred compensation are involved; either parent's income is disputed, imputed or largely non-cash; a child has special needs or disability; support is above a statutory cap; or the other party already has a lawyer. A lawyer can also advise on deviation factors, add-ons and enforcement in that jurisdiction — none of which a guideline calculator can decide. This site cannot recommend a specific lawyer and does not take referral fees.
Frequently asked questions
These questions are shown on the page in full. They are not marked up as FAQ structured data.
What incomes go into the California formula?
Net monthly disposable income under §4059 — gross income minus only tax, FICA, mandatory dues/retirement, health premiums, ordered support paid, allowed job expenses and hardship deductions.
Is there a California child support cap?
No dollar cap and no fixed high-income threshold. Deviation for extraordinarily high income exists, but the statute does not define it by a dollar figure.
How are add-ons split in California now?
In proportion to the parents' net incomes as adjusted by §4061(c)–(d), operative 1 September 2024 — not by an older half-and-half default.
Does California have a child support cap?
No dollar cap. Support is formula-driven at any income, subject to deviation — including for extraordinarily high income, which the statute does not define by a dollar figure.
What happens if timeshare changes?
Because H% is in the formula, a change in timeshare changes the guideline figure directly. A modification generally requires a material change in circumstances; this calculator does not decide whether a change qualifies.
Change log
| Date | Change |
|---|---|
| October 2026 | Initial build: formula, cap and worked examples from official sources, dated October 2026. |
| October 2026 | Remediation pass: FAQPage structured data removed and replaced with BreadcrumbList plus WebApplication/Article schema; visible FAQ added; navigation replaced with three hub pages and same-jurisdiction Related links; author byline and author box added; clean folder URLs. No calculator formula, cap or worked-example figure was changed in this pass. |
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