About the CA calculator

This is a free child support guideline calculator for California. It estimates the amount of monthly child support based on California Family Code §§ 4055 and 4059. It's private, anonymous, and separate from the CA Department of Child Support Services (DCSS). We don't store or transmit any of your personal information.

How it works

Guideline formula (§4055)

California uses one statewide guideline formula (Family Code §4055). Every county and every judge starts here. The formula is:

CS = K × [HN − (H% × TN)]

Where CS is monthly child support for one child, HN is the higher earner's monthly net disposable income, TN is both parents' combined monthly net, H% is the higher earner's share of primary physical responsibility (their timeshare with the child), and K is a fraction (the "income allocation factor") that rises with combined income. For more than one child, the result is multiplied by a per-child factor: 1.6 (2 kids), 2 (3 kids), 2.3 (4 kids), 2.5 (5 kids), and so on, per §4055(b)(4).

The K factor itself is a bracketed table that depends on the combined monthly net disposable income — see the table in §4055(b)(3). Our calculator uses the current statutory table.

Net disposable income (§4059)

HN and TN aren't gross paycheck numbers — they're net disposable income per §4059: gross income (from any §4058 source — wages, self-employment, interest, dividends, capital gains, rental, retirement, unemployment, workers' comp) minus federal income tax, California state income tax, FICA / SE tax, CA SDI, mandatory retirement and union dues, health-insurance premiums, child-support paid for other children, and job-related expenses. Our calculator runs the full TY 2026 federal + California tax pipeline to produce these numbers — including all OBBBA (PL 119-21) provisions.

Add-ons (§4062)

The guideline number above covers basic support. On top of it, courts usually order specific extras under §4062. These are typically listed separately on the support order and split between the parents by income share per §4061(b)(2) — i.e., whichever parent earns 60% of the combined net pays 60% of the add-on.

Mandatory (§4062(a)): childcare costs needed for either parent to work or get job-related training, and reasonable uninsured health-care costs for the children.
Discretionary (§4062(b)): educational or other special-needs costs, and travel expenses for visitation.

Add-ons are typically not added into the CS amount you'll see on the order — they're a separate line item that gets reimbursed or paid proportionally as costs are incurred.

Low-Income Adjustment (§4055(b)(7))

When the paying parent's monthly net falls below full-time California minimum-wage gross ($2,929/mo at 40 hours/week for 2026), §4055(b)(7) creates a rebuttable presumption of a reduced support amount. The maximum reduction is CS × (threshold − net) / threshold. Our calculator applies the maximum reduction by default as this is the guideline estimate (the usual outcome when the presumption isn't rebutted); a judge can rebut and apply a smaller reduction under §4053 principles.

CalWORKs pass-through (AB 207)

If the receiving parent receives CalWORKs (cash aid), they must assign their right to the child support to the state as a condition of receiving aid. The state then collects the support and keeps it to reimburse the cash assistance, passing only part of it through to the family — up to $100/mo for one child and $200/mo for two or more (AB 207). Our calculator still computes the full guideline number — that's what the paying parent owes — but flags this pass-through when you mark the receiving parent as receiving CalWORKs, so you can see what the family actually takes home.

Tax assumptions

When we estimate child support based on the minimally required questions – children, parenting time, and incomes – our calculator makes some simple assumptions about your tax situation:

All income is W-2 wages. FICA and CA SDI are withheld. Self-employment, investment, rental, retirement, and other income types can be entered in More Details and are taxed by their own rules.
Filing status follows parenting time. The parent with more than 50% timeshare is presumed to file Head of Household and claim all of the children as dependents; the other parent files Single with no dependents. At exactly 50/50, both parents are presumed Single.
Standard deduction. Both parents take the standard deduction.
Tax credits are applied automatically. The Child Tax Credit, federal EITC, and CalEITC / Young Child Tax Credit go to the parent presumed to claim the children, whenever their income qualifies.
No other paycheck deductions. Health-insurance premiums, mandatory retirement and union dues, support paid for other children, and hardship deductions are treated as $0.

Accuracy and testing

Our calculator matches a California state-certified calculator to within 1% across all 141 scenarios we've tested.*

Test category	Example scenario	Scenarios	Guideline calculation (ours & state-certified match)
Baseline §4055	1 kid · Parent A $12,000/mo (20% time) · Parent B $6,000/mo	50
§4059 deductions §4059(c)–(d)	1 kid · Parent A $6,000/mo wages (20% time) with $400/mo mandatory retirement · Parent B $3,000/mo	4
Self-employment §1401 + §199A	1 kid · Parent A Schedule C net $5,000/mo (20% time) · Parent B $3,000/mo wages	8
Mixed income §4058	1 kid · Parent A $6,000/mo wages (20% time) + $200/mo interest + $100/mo qualified div · Parent B $3,000/mo	6
Itemized deductions IRC §63	1 kid · Parent A $8,000/mo (20% time) + $12k mortgage interest, $6k property tax, $1k charity (annual) · Parent B $4,000/mo	6
Aged 65+ IRC §63(f)	1 kid · Parent A $5,000/mo (age 65+, 20% time) · Parent B $3,000/mo	4
Add-on (childcare) §4062(a)(1)	1 kid · Parent A $7,000/mo (20% time) + $1,200/mo work-related childcare · Parent B $4,000/mo	1	$488/mo
Hardship (medical) §4071(a)(1)	1 kid · Parent A $7,000/mo (20% time) + $800/mo extraordinary uninsured medical · Parent B $4,000/mo	1	$853/mo
Low-Income Adjustment §4055(b)(7)	1 kid · Parent A $2,500/mo (20% time) · Parent B $6,000/mo	1	$150/mo
OBBBA tips §70201	1 kid · Parent A $3,500/mo wages (20% time) + $1,500/mo qualifying tips · Parent B $3,000/mo	5
OBBBA overtime §70202	1 kid · Parent A $5,000/mo wages (20% time) + $500/mo qualified OT premium · Parent B $3,000/mo	5
OBBBA senior bonus §70103	1 kid · Parent A $4,200/mo (age 65+, 20% time) · Parent B $3,000/mo	4
OBBBA charity §70424	1 kid · Parent A $5,000/mo (20% time) + $1,000/yr charitable giving · Parent B $3,000/mo	3
Other edge cases mixed	AMT, NIIT, Additional Medicare, 4+ children, MFJ, HoH, OBBBA Trump/SALT/CTC, multi-add-on bundles	44

Common questions

How does California figure out child support?: California uses a formula that looks at both parents' income after taxes and how much time each parent spends with the children. The parent who earns more and spends less time with the children usually pays support.; The guideline formula is CS = K × [HN − H% × TN], where K is an income-allocation factor, HN is the higher-earning parent's net monthly income, H% is their percentage of parenting time, and TN is total combined net monthly income. For multiple children, the amount is multiplied by a factor (1.6 for 2 children, 2.0 for 3, etc.).
What counts as income?: Almost everything: your paycheck, tips, bonuses, money from a side job, rental income, Social Security, unemployment, and more. The main things that don't count are food stamps, SSI, and TANF.; Per Family Code §4058, gross income includes wages, salary, commissions, bonuses, self-employment income, rental income, royalties, interest, dividends, capital gains, workers' compensation, unemployment, disability, Social Security, and spousal support received. Public assistance (TANF, SSI) is generally excluded.
Does overtime count?: Usually yes, if you regularly work overtime. If it's a one-time thing, the judge might not count it.
What if I don't make much money?: If the paying parent's income after taxes is below about $2,929 per month (the amount you'd earn working full-time at minimum wage), the support amount may be lower. This is called the Low-Income Adjustment.; Per §4055(b)(7), when the monthly net disposable income of the parent paying support is below full-time CA minimum wage (~$2,929/month in 2026 at $16.90/hour), there is a rebuttable presumption that a reduced support amount applies.
What are add-ons?: Add-ons are extra costs on top of regular child support. The main ones are childcare (so you can work) and out-of-pocket medical expenses. These costs are split between parents based on income.; Per §4062, mandatory add-ons include childcare for work/education and reasonable uninsured health care. Discretionary add-ons include education expenses and travel for visitation. Split by income share per §4061(b).
Is this the official amount I'll pay?: No. This is an estimate to help you plan. A judge or child support commissioner decides the official amount. They may set it higher or lower depending on your situation.
What tax year does this use?: Our calculators use 2026 tax rates.
Is my personal information saved?: We don't collect or store any personally identifiable information about you.
Are you the government?: No, we are not the government. We are a private company – separate from the Department of Child Support Services – and we do not share any of your personal information with them.
How accurate is this?: Very accurate. We tested our calculator against the government certified calculators and the results match within $1 for over 100 scenarios we tested. Read more about our accuracy testing.
Where can I get help?: Your local Family Law Facilitator can help you for free. They're available at every California courthouse. You can also contact your county's Department of Child Support Services (DCSS). Find your court's self-help center.

Glossary

Key terms

Timeshare: How much time each parent spends with the children. Usually measured in overnights per month.; The high earner's approximate percentage of primary physical responsibility for the children (H%). Derived from overnights per month (out of 30).
Net disposable income: Money you have left after paying taxes and required deductions.; Per §4059: Gross income minus federal income tax, CA state tax, FICA/SE tax, CA SDI, and §4059(c)–(g) direct deductions.
Gross income: All the money you earn before taxes are taken out.; Per §4058: All income from any source including wages, self-employment, interest, dividends, capital gains, rental, retirement, Social Security, unemployment, and workers comp. Public assistance (TANF, SSI) excluded per §4058(c).
Low-Income Adjustment (LIA): A rule that may lower child support if the paying parent doesn't earn much money.; Per §4055(b)(7): Rebuttable presumption of reduced support when the monthly net of the parent paying support is below full-time minimum wage gross ($2,929 for 2026). Reduction formula: CS × (threshold − net) / threshold.

Tax credits

EITC: A tax credit for people who work but don't earn a lot. It can give you money back.; Earned Income Tax Credit: Federal refundable credit phased in, plateaus, and phases out based on earned income and filing status.
CTC: A tax credit for having children. Worth up to $2,200 per child in 2025.; Child Tax Credit: For 2025 (post-OBBBA), $2,200 per qualifying child under age 17.
CalEITC: California's version of the federal EITC. Extra money back if you qualify.; California Earned Income Tax Credit: State refundable credit with a hard income ceiling of $31,950.
YCTC: California credit for parents with young children (under 6). Worth $1,154 per child.; Young Child Tax Credit: California refundable credit of $1,154 per dependent under age 6.

Paycheck deductions

FICA: Money taken from your paycheck for Social Security and Medicare. About 7.65% of your pay.; Federal Insurance Contributions Act: 6.2% Social Security on wages up to $176,100 (2025), plus 1.45% Medicare on all wages, plus 0.9% Additional Medicare above filing-status threshold.
SDI: California disability insurance taken from your paycheck. About 1.2% of your pay.; California State Disability Insurance: 1.2% for 2025, 1.3% for 2026, no wage cap since SB 951.
Self-employment tax: If you work for yourself, you pay both the employee and employer share of Social Security and Medicare.; Per IRC §1401: Combined employee and employer portion of SS/Medicare for self-employed. Computed as 15.3% × 92.35% of net SE earnings.

Add-ons (extra costs)

Childcare add-on: Daycare or babysitting costs so a parent can work or go to school. Split between parents based on income.; Per §4062(a)(1): Mandatory add-on for reasonable childcare costs incurred to work or obtain work-related education/training.
Health care add-on: Out-of-pocket medical costs for the children not covered by insurance.; Per §4062(a)(2): Mandatory add-on for reasonable uninsured health-care costs for the children.

Hardship

Hardship deduction: If you have unusual expenses (major medical bills, big losses, other children to support), you may qualify for reduced support.; Per §4070: Reductions from net disposable income for extraordinary health expenses, catastrophic loss, or minimum basic living expenses for other natural/adopted children residing with the parent.

Tax filing

Single: Filing status if you're not married and don't qualify for head of household.
Head of Household: Filing status if you're not married, pay more than half the household costs, and have a child living with you more than half the year. Usually gives better tax rates.; Unmarried filer who paid more than half the cost of keeping up a home and had a qualifying dependent living with them for more than half the year.
Married Filing Jointly: Filing status for married couples who file one tax return together.
Married Filing Separately: Filing status for married couples who each file their own tax return.

Formula terms

K multiplier: A number used in the formula that factors in both parents' incomes and time with the children.; Per §4055(b)(3): The income-allocation factor computed from total net monthly income and the high earner's timeshare.
HN: The higher-earning parent's monthly income after taxes.; High earner's net monthly disposable income.
TN: Both parents' combined monthly income after taxes.; Total net monthly disposable income of both parents combined.
Multi-child multiplier: Support goes up for more children, but not by the same amount for each: 2 kids = 1.6×, 3 kids = 2×, and so on.; Per §4055(b)(4): 1 child = 1.0, 2 = 1.6, 3 = 2.0, 4 = 2.3, up to 10 = 2.86.

Disclaimers

Not legal advice. This is an estimate for informational purposes. We do our best to be as accurate as possible, but for advice on your specific situation, talk to a family-law attorney or your county's Family Law Facilitator.
Not an official estimate. If you need an official calculation for a court order, use a state-certified calculator or ask your Family Law Facilitator.
Not certified or CPA-reviewed. As of May 2026, our calculator has not been reviewed by a CPA and is not on the Judicial Council's list of state-certified guideline calculators.
Income is taken as entered. Our calculator does not impute earning capacity. Voluntary-unemployment or underemployment adjustments under §4058(b) are judicial determinations, not guideline calculations.

Need help?

Every California courthouse has a free Family Law Facilitator who can help you. You can also call your county's Department of Child Support Services (DCSS) or visit childsupport.ca.gov.

OBBBA auto-loan interest. The One Big Beautiful Bill Act (PL 119-21, July 4, 2025) added an above-the-line deduction for qualified passenger-vehicle loan interest payments (up to $10,000/yr, §70203). Our calculator supports this deduction. Some JCC-certified guideline calculators do not yet implement it, so scenarios that exercise §70203 are excluded from the parity-comparison count above to keep the test apples-to-apples.

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