How to Use the California Child Support Calculator
Enter what you know and press Calculate Estimate. The calculator estimates each parent's net disposable income and applies the California guideline formula step by step.
- Enter each parent's gross monthly income as Parent A and Parent B.
- Choose the number of children and the parent the children live with most of the time.
- Enter the overnights per year the children spend with the other parent. California's formula uses time-sharing directly, so this number matters at any level.
- Add monthly work-related child care and the child's health insurance premium, and say which parent pays them.
Your numbers are sent with the form, not placed in the page address, and this site does not store them. The result is a planning estimate; a California court decides the actual amount.
New California Child Support Laws and Changes for 2026
Looking for new child support laws in California for 2026? The big change is SB 343, which updated the Family Code § 4055 guideline for orders from September 1, 2024: new K-factor income bands, a low-income adjustment tied to the full-time minimum wage, and default allocation of add-ons by net income. Two 2026 numbers feed into it: the statewide minimum wage of $16.90 an hour raises the low-income threshold to about $2,929 a month, and the SDI withholding rate is 1.3% for 2026, which reduces net disposable income. The calculator above uses both.
SB 343 applies to new orders and modifications; existing orders do not change automatically.
How California Calculates Child Support: The Guideline Formula
California does not use a lookup table. Family Code § 4055 sets a statewide formula, which changed for new orders on September 1, 2024 under SB 343:
CS = K [HN − (H%)(TN)]
- CS is the basic monthly child support amount.
- HN is the high earner's net monthly disposable income.
- TN is the total net monthly disposable income of both parents.
- H% is the approximate percentage of time the high earner has primary physical responsibility for the children compared with the other parent.
- K is (1 + H%) if H% is 50% or less, or (2 − H%) if H% is more than 50%, multiplied by a fraction that depends on TN (below).
| Total net disposable income per month (TN) | Fraction |
|---|
| $0 to $2,900 | 0.165 + TN / 82,857 |
| $2,901 to $5,000 | 0.131 + TN / 42,149 |
| $5,001 to $10,000 | 0.25 |
| $10,001 to $15,000 | 0.10 + 1,499 / TN |
| Over $15,000 | 0.12 + 1,200 / TN |
If the result is positive, the higher earner pays the lower earner. If it is negative, the lower earner pays the higher earner. For more than one child, the one-child result is multiplied by a factor:
| Number of children | Multiplier |
|---|
| 1 | 1 |
| 2 | 1.6 |
| 3 | 2 |
| 4 | 2.3 |
| 5 | 2.5 |
| 6 | 2.625 |
The formula result is the starting point. The court can then add child care and uninsured health costs and consider deviations.
Net Disposable Income: How This Calculator Estimates It
Family Code § 4059 lets the court subtract from gross income: state and federal income taxes, FICA (or equivalent), mandatory union dues and retirement, health insurance premiums for the parent and the children, state disability insurance (SDI) premiums, support paid to others, allowed job-related expenses and hardship.
This calculator estimates net disposable income from gross income by subtracting federal income tax (2025 brackets, standard deduction), California income tax (2025 Schedule X rates, standard deduction and exemption credit), FICA at 7.65% and SDI at 1.3% (the 2026 rate, with no wage cap). The health insurance premium you enter is deducted from the net income of the parent who pays it. The estimate does not apply the other deductions, so your real net disposable income may differ.
Low-Income Adjustment Under SB 343
If the paying parent's net disposable income is less than the monthly gross income from full-time minimum wage (40 hours a week, 52 weeks a year), there is a rebuttable presumption that they are entitled to a low-income adjustment. Before SB 343 the threshold was a fixed $1,500; it now rises with the minimum wage. At the 2026 California minimum wage of $16.90 an hour, the threshold is about $2,929 a month.
The adjustment can reduce the guideline amount by up to the fraction (threshold − obligor's net income) ÷ threshold. The court can use any amount in the resulting range, and can rebut the presumption if the lowest amount would be unjust or inappropriate. The calculator shows the lowest allowed amount and explains the range.
California Child Support Examples
These examples start from net disposable income so you can follow the formula. In each, the children live with Parent B.
Example 1: One child, no time with the high earner
Parent A's net is $6,000, Parent B's is $2,000, TN = $8,000. The high earner (A) has 0% of the time, so H% = 0 and K = 1 × 0.25 = 0.25. CS = 0.25 × $6,000 = $1,500 a month.
Example 2: Two children
Same incomes. $1,500 × 1.6 = $2,400 a month.
Example 3: Parent A has about 30% of the time
Same incomes, one child, 110 overnights a year with Parent A (H% ≈ 30.1%). K = 1.301 × 0.25. CS = K × ($6,000 − 0.301 × $8,000) = $1,167.67 a month, down from $1,500.
Example 4: Low-income adjustment
Parent A's net is $2,000 and Parent B's is $1,000. The formula gives about $404, but because A's net income is below the $2,929 threshold, the lowest amount after the adjustment is $276.07 a month.
Example 5: Child care
Example 1 plus $600 a month of child care paid by Parent B. Parent A's share of net income is 75%, so A adds $450: $1,950 a month.
Example 6: High income
Parent A's net is $12,000 and B's is $4,000; TN = $16,000 so the fraction is 0.12 + 1,200 ÷ 16,000 = 0.195. For two children: 0.195 × $12,000 × 1.6 = $3,744 a month.
These are illustrations produced from the statute's formula, not court rulings.
California Child Support With 50/50 Custody or Shared Time
If you are looking for a 50/50 child support calculator for California, the formula already accounts for time-sharing. There is no overnight threshold: the high earner's share of time (H%) is part of the equation at every level.
- The more time the higher earner has with the children, the lower the result. At exactly 50/50, K = 1.5 × the income fraction, and the amount is based on half of the difference between the parents' net incomes.
- If the higher earner has more than 50% of the time, K switches to (2 − H%). The result can turn negative, which means the lower earner pays.
- For children on different schedules, H% is the average of the percentages for each child.
Enter the overnights per year with the other parent and the calculator works out H% for you.
Frequently Asked Questions About California Child Support
Is this the official California child support calculator?
No. ChildSupportCalculator.xyz is an independent tool and is not affiliated with the state or any court. It applies the formula in Family Code 4055 as amended by SB 343. The California Department of Child Support Services and the courts decide actual amounts.
How is child support calculated in California?
California uses the guideline formula CS = K[HN − (H%)(TN)]: the higher earner's net disposable income, minus the high earner's time-share percentage times total net income, multiplied by a K factor, and multiplied again for more than one child. Child care and other add-ons are then considered.
What changed in California child support in 2024?
SB 343 rewrote the K-factor income bands, tied the low-income adjustment to the full-time minimum wage instead of a fixed $1,500, and made add-ons such as child care and uninsured health costs split by net income by default. It applies to orders from September 1, 2024.
Does California use gross or net income?
Net disposable income. It is gross income minus allowed deductions such as income taxes, FICA, mandatory union dues and retirement, health insurance premiums and state disability insurance. This calculator estimates it from gross income.
How does 50/50 custody affect child support in California?
The formula includes the high earner's time-share percentage, so more time with the higher earner lowers the result. At 50/50 the amount is based on half the difference in net incomes, and if the higher earner has more than half the time the lower earner may pay.
Is there a minimum number of overnights for a shared-time adjustment in California?
No. Unlike many states, California has no overnight threshold; time-sharing changes the result at every level through H%.
What is the California low-income adjustment?
If the paying parent's net disposable income is below the monthly gross income from full-time minimum wage (about $2,929 at the $16.90 rate for 2026), there is a rebuttable presumption of a reduction of up to the fraction (threshold − net income) ÷ threshold.
Does California child support include child care?
Yes. Child care related to employment is a mandatory add-on under Family Code 4062, divided by the parents' net disposable incomes unless a different split is requested or ordered.
Does this calculator include alimony, arrears or modification?
No. It estimates a new guideline amount only. Spousal support, past-due support and modification depend on your case; check with the court or an attorney.
Can I get an official child support estimate in California?
The California Department of Child Support Services and your county child support agency can explain the process, and courts use the statewide formula and Judicial Council forms. See the official resources linked below.
Are there new child support laws in California in 2026?
SB 343 updated the California guideline for orders from September 1, 2024. In 2026 the minimum wage of $16.90 raises the low-income adjustment threshold to about $2,929 a month, and the SDI rate is 1.3%. Existing orders do not change automatically.
