About QuickCalc
QuickCalc 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). QuickCalc 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. QuickCalc 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.
QuickCalc 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). QuickCalc 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.
Accuracy and testing
QuickCalc matches California's state-certified calculator to within 1% across all 140 scenarios we've tested:*" .
| Test category | Example scenario | Scenarios | Guideline calculation (QuickCalc & state-certified match) |
|---|---|---|---|
| Baseline §4055 | 1 kid · NCP $12,000/mo, OP $6,000/mo · NCP 20% time | 50 | |
| §4059 deductions §4059(c)–(d) | 1 kid · NCP $6,000/mo wages with $400/mo mandatory retirement · OP $3,000/mo · 20% time | 4 | |
| Self-employment §1401 + §199A | 1 kid · NCP Schedule C net $5,000/mo · OP $3,000/mo wages · 20% time | 8 | |
| Mixed income §4058 | 1 kid · NCP $6,000/mo wages + $200/mo interest + $100/mo qualified div · OP $3,000/mo · 20% time | 6 | |
| Itemized deductions IRC §63 | 1 kid · NCP $8,000/mo + $12k mortgage interest, $6k property tax, $1k charity (annual) · OP $4,000/mo · 20% time | 6 | |
| Aged 65+ IRC §63(f) | 1 kid · NCP $5,000/mo (age 65+) · OP $3,000/mo · 20% time | 4 | |
| Add-on (childcare) §4062(a)(1) | 1 kid · NCP $7,000/mo + $1,200/mo work-related childcare · OP $4,000/mo · 20% time | 1 | $488/mo |
| Hardship (medical) §4071(a)(1) | 1 kid · NCP $7,000/mo + $800/mo extraordinary uninsured medical · OP $4,000/mo · 20% time | 1 | $853/mo |
| Low-Income Adjustment §4055(b)(7) | 1 kid · NCP $2,500/mo · OP $6,000/mo · 20% time | 1 | $150/mo |
| OBBBA tips §70201 | 1 kid · NCP $3,500/mo wages + $1,500/mo qualifying tips · OP $3,000/mo · 20% time | 5 | |
| OBBBA overtime §70202 | 1 kid · NCP $5,000/mo wages + $500/mo qualified OT premium · OP $3,000/mo · 20% time | 5 | |
| OBBBA senior bonus §70103 | 1 kid · NCP $4,200/mo (age 65+) · OP $3,000/mo · 20% time | 4 | |
| OBBBA charity §70424 | 1 kid · NCP $5,000/mo + $1,000/yr charitable giving · OP $3,000/mo · 20% time | 3 | |
| Other edge cases mixed | AMT, NIIT, Additional Medicare, 4+ children, MFJ, HoH, OBBBA Trump/SALT/CTC, multi-add-on bundles | 44 |
Disclaimers
- Not legal advice. QuickCalc 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, QuickCalc 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. QuickCalc 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). QuickCalc 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.