Understand what variables actually drive the state's child support calculator—and how courts punish parents who intentionally earn less to avoid support obligations.
California's child support formula (Family Code § 4055) is a complex algebraic equation. These are the real inputs that determine your monthly obligation—not guesses, not wishes, but hard data points the court will verify.
CS = K[HN - (H%)(TN)]
All income sources: wages, salaries, commissions, bonuses, overtime, self-employment income, rental income, dividends, interest, pensions, unemployment benefits, and workers' compensation. The court looks at your last 12 months to establish a pattern.
Federal and state income tax, FICA (Social Security and Medicare), mandatory union dues, mandatory retirement contributions, and health insurance premiums for the child(ren). These reduce gross income to "net disposable income."
If you have children from other relationships for whom you pay court-ordered support, or children living with you from another partner, you receive a deduction. This is not automatic—you must prove the obligation.
Spousal support you receive counts as income. Spousal support you pay is deductible. The calculator treats these as adjustments to net disposable income, which can significantly shift the support number.
The percentage of time the higher-earning parent has physical custody of the child. This is the single most powerful variable after income. A 20% timeshare vs. 40% timeshare can swing support by hundreds of dollars monthly. Courts count overnights, not hours.
The cost to add the child(ren) to your health insurance plan. If you already have family coverage, only the marginal cost to add the child is counted. The calculator credits the paying parent for this expense.
Work-related childcare expenses: daycare, before/after school care, nannies. Must be necessary for employment or education. Babysitting for date nights doesn't count. Costs are split proportionally to income.
Out-of-pocket medical, dental, and vision costs not covered by insurance. Co-pays, prescriptions, orthodontic work, therapy. These are typically split 50/50 unless the court orders otherwise based on income disparity.
Private school tuition, tutoring, special education costs if agreed upon or court-ordered.
Long-distance travel for visitation, especially in geographic separation cases.
Sports, music, arts, camps—if agreed or historically paid by both parents.
Generally excluded, but if it dramatically reduces expenses (free housing), courts may consider.
Repayments on 401(k) loans may be deductible if taken for marital purposes.
In sole-occupancy situations, mortgage principal payments on the family home may be credited.
California courts refuse to let parents game the system. If you voluntarily earn less than you're capable of, the court can "impute" income—assigning you a higher earning capacity for support calculations.
Quitting a high-paying job shortly before or after separation without a comparable replacement
Refusing promotions or overtime that were previously accepted, especially when tied to support proceedings
Working part-time when full-time work is available in their field and was previously performed
Career regression—taking a job far below education, experience, and prior earnings level without justification
Concealing income through cash payments, cryptocurrency, or under-the-table work
Failing to seek work when unemployed, especially with marketable skills and available opportunities
The court examines your education, training, work history, job skills, age, health, and local job market. A software engineer who quits to "find themselves" will likely be imputed at their prior salary.
The imputed income replaces actual income in the DissoMaster or Xspouse calculation. You pay support based on what you could earn, not what you choose to earn.
The parent seeking imputation must prove the other parent voluntarily reduced income. The defending parent can argue legitimate reasons: disability, layoffs, market conditions, or career changes for children's benefit.
Family Code § 4059(b) allows courts to consider "hardship" deductions from income. However, this is narrowly construed. Voluntary choices that reduce income (quitting to start a business, moving to a lower-paying area) generally don't qualify. True hardships include: catastrophic medical expenses for a child, mandatory job loss with documented search efforts, or disability. Even then, the hardship deduction is discretionary—not guaranteed.
Key insight: Courts distinguish between "can't earn" and "won't earn." If you have a documented disability, layoff, or market collapse, bring evidence: medical records, termination letters, job applications, industry reports. Without documentation, the court will impute your prior earnings.
Understanding the calculator's mechanics lets you plan effectively—whether you're the paying or receiving parent.
Keep pay stubs, tax returns, W-2s, 1099s, childcare receipts, and insurance premium statements for the last 2–3 years. The court averages income over time to prevent manipulation.
The calculator uses overnights, not total hours. A parent with Thursday dinner + every other weekend has about 20% timeshare. Add one midweek overnight and you hit 30%—a significant support reduction.
If you remarry and have a new child, you can request a hardship deduction. But you must actually have the child and be supporting them—not just be pregnant or planning.
Irregular income (bonuses, commissions, stock options) is typically averaged over 12–24 months. If you had one exceptional year, argue for a longer averaging period to normalize the number.
If one parent retains the family home and pays the mortgage, the court may credit mortgage principal as a child support add-on or adjust spousal support, which indirectly affects child support.
The guideline amount is presumptively correct, but courts can deviate for extraordinary circumstances: travel costs for visitation, child's special needs, or extremely high income where the formula produces a windfall.
Online calculators give estimates. We run the actual DissoMaster software used by California courts—accounting for every variable, deduction, and add-on that affects your specific case.
Whether you're facing imputation accusations or seeking to impute income to an underemployed ex, we know the evidence courts require.
