How California Calculates Child and Spousal Support in 2026

California calculates child support with one statewide formula, Family Code §4055: CS = K[HN − (H%)(TN)]. It runs on both parents' net monthly incomes and the high earner's share of parenting time. Its income bands were rewritten on September 1, 2024. Spousal support comes in two kinds. While the case is pending, the California Courts Self-Help Guide says most courts set temporary support with a math formula. For long-term support, the same guide says there is no formula; the judge weighs the factors in Family Code §4320.

Key figures

• Over $15,000 a month combined net income: top child support band, since September 1, 2024 (§4055).
• $2,929 a month: low-income adjustment threshold, from January 1, 2026.
• 40% payor net minus 50% payee net, tax-adjusted: Santa Clara's temporary spousal support formula (Local Family Rule 3(C), as published on the court's site, Rule 3 last dated 2021).
• 10 years, marriage to separation: long-duration presumption (§4336).
• January 1, 2026: spousal support under instruments executed on or after this date is neither deductible nor taxable in California (SB 711).

How is child support calculated in California?

California child support starts from one formula in Family Code §4055: CS = K[HN − (H%)(TN)]. HN is the high earner's net monthly disposable income, and TN is both parents' total. H% is the approximate percentage of time the high earner "has or will have primary physical responsibility for the children compared to the other parent." K is the share of combined income allocated to child support. CS is the amount for one child.

Combined income sets K's base fraction from the band table below. Parenting time then multiplies it: by (1 + H%) when H% is 50% or less, and by (2 − H%) above that. On the statute's terms, the multiplier peaks at 1.5, at an even split. For more children, §4055(b)(4) multiplies CS: 1.6 for two, 2 for three, up to 2.86 for ten.

An illustration, worked from the statute's terms and not an estimate of any order: TN of $10,000, HN of $6,000 and H% of 20%. Under the bands in force since September 1, 2024, the fraction is 0.25, so K is 1.2 × 0.25 = 0.30. CS is 0.30 × ($6,000 − $2,000) = $1,200 a month for one child.

The formula amount is presumed correct (§4057(a)), but admissible evidence that applying the formula would be unjust or inappropriate in the case can rebut it (§4057(b)). As amended by SB 343 from September 1, 2024, §4057(b) still allows rebuttal where the paying parent has an extraordinarily high income and the guideline amount would exceed the children's needs.

What counts as income for California child support?

California child support uses net disposable income: gross income minus the deductions in Family Code §4059. The main ones are:

• state and federal income tax, matched to the parent's filing status and number of dependents;
• FICA contributions as an employee or self-employed worker (§4059(b));
• mandatory union dues and retirement benefits required as a condition of employment (§4059(c));
• health insurance premiums for the parent and children they must support, and state disability insurance premiums (§4059(d));
• court-ordered child or spousal support actually paid for someone outside the order being set, if the parent proves payment (§4059(e)).

Under §4058(b), as rewritten by SB 343 from September 1, 2024, a court can look at earning capacity instead of actual pay. It must consider earning capacity when a parent's income is unknown. When income is known, it may use earning capacity in its discretion, consistent with the children's best interests. It weighs the parent's circumstances, among them assets, work history, skills, health and the local labor market. Incarceration or involuntary institutionalization is not treated as voluntary unemployment (§4058(b)).

What changed in California's child support bands on September 1, 2024?

On September 1, 2024, SB 343 (Chapter 213, Statutes of 2023) replaced §4055's income bands with five bands of combined net monthly income (TN):

Since September 1, 2024, the top band covers combined net monthly income over $15,000 and has no ceiling. Before September 1, 2024, the table had four bands, with edges at $800, $6,666 and $10,000, and its top band used 0.12 + 800/TN.

In arithmetic on the statute's coefficients, the September 1, 2024 change moved the base fraction from 0.25 to about 0.18 at $1,000 of combined net monthly income, from 0.20 to 0.25 at $10,000, and from 0.16 to 0.18 at $20,000.

The Judicial Council's guideline review, sent to the Legislature on June 3, 2026, calls the 2024 changes the first time the formula's percentages and income ranges were changed. Its recommendations are not law unless the Legislature enacts them.

The low-income adjustment threshold is $2,929 a month from January 1, 2026. It works as a rebuttable presumption that applies when the paying parent's own net disposable income is below that amount (§4055(b)(7)). Since September 1, 2024, the threshold has equalled full-time pay at the state minimum wage: $16.90 an hour from January 1, 2026, times 40 hours, times 52 weeks, divided by 12. It replaced a consumer-price-indexed figure used from March 1, 2013 to August 31, 2024.

How are add-on costs split in California child support?

Since September 1, 2024, California shares add-on costs in proportion to the parents' net disposable incomes under Family Code §4061, as adjusted under §4061(c) and (d). A party, or the court on its own motion, can ask for a different split.

Under §4062, the court must add child care costs actually incurred for work, or for reasonably necessary education or training for job skills. It must also add reasonable uninsured health care costs for the children, as §4063 provides. It may add costs for the children's educational or other special needs, and travel for visitation.

Before September 1, 2024, §4061 split these costs one-half to each parent, unless a parent asked for another split and documented why it was more appropriate.

How is temporary spousal support calculated in California?

The California Courts Self-Help Guide says most courts set temporary spousal support with a math formula, which the judge can vary. Family Code §3600 lets the court order either spouse to pay the other's support while a divorce or legal separation is pending.

The guide's example is 40% of the higher earner's net monthly income minus 50% of the lower earner's. That is an example, not a statewide rule. Santa Clara and Alameda are two counties with a written formula in their local rules:

• Santa Clara County's Local Family Rule 3(C), as published on the court's site with Rule 3 last dated 2021, generally computes temporary spousal support as 40% of the payor's net income minus 50% of the payee's, adjusted for tax consequences. Where there is child support, Santa Clara's rule, not a statewide one, uses net income not allocated to child support and child-related expenses.
• Alameda County's Local Rule 5.70, in the Title 5 rules dated July 1, 2026, uses 40% of the payor's net income minus 50% of the payee's where there is no child support. Where there is, it uses a separate formula built from §4055's terms.

How is long-term spousal support decided in California?

Long-term spousal support in California has no formula, according to the California Courts Self-Help Guide. The judge weighs the factors in Family Code §4320. On the guide's terms, when spouses write up an agreement to change long-term support, the new amount can't be based on a support calculator program.

Outside a marriage of long duration, §4320 says a reasonable period to become self-supporting "generally shall be one-half the length of the marriage." The same section says nothing in it limits the court's discretion to order support for a longer or shorter time.

Family Code §4336 presumes a marriage of 10 years or more is of long duration, measured from marriage to separation, not filing. The presumption is for retaining jurisdiction and affects the burden of producing evidence; the court may consider separation periods during the marriage.

§4320(i) requires the court to consider documented evidence of domestic violence, as defined in §6211, between the parties or against either party's child. §4320(m) requires it to consider an abusive spouse's criminal conviction when reducing or eliminating support. §4325 presumes support is prohibited for a spouse convicted of a domestic-violence misdemeanor against the other within five years before the divorce filing or during the divorce proceeding. A misdemeanor resulting in probation under Penal Code §1203.097 also counts. The presumption is rebuttable; its current wording applies to convictions on or after January 1, 2019.

Is spousal support tax deductible in California in 2026?

For California income tax, it depends on when the divorce or separation instrument was executed. The Franchise Tax Board gives two rules:

• Executed before January 1, 2026: payments generally remain deductible by the payer and taxable to the recipient in California. California did not conform to the federal post-2018 rule. That changes only if the instrument is modified after 2025 and expressly adopts the SB 711 amendments.
• Executed on or after January 1, 2026: payments are neither deductible by the payer nor income to the recipient in California, under SB 711 (Chapter 231, Statutes of 2025, chaptered October 1, 2025).

The IRS applies that rule to instruments executed after December 31, 2018. Read together, the IRS and FTB rules treat a 2026 instrument the same way, while an unmodified 2020 instrument generally gets different answers. This is general tax information, not tax advice.

Not covered here: Title IV-D agency cases, hardship and job-expense deductions, and how spousal support affects child support income.

California support at a glance, 2026

The recent changes date from September 1, 2024 (child support) or January 1, 2026 (low-income threshold and California tax).

This article is general legal information about California law as of October 2026, not legal advice. Statutes and indexed figures change; confirm current figures with the cited source or a licensed California attorney. Published by Aparti.