California Family Code Section 4061 tells divorced or separated parents how to split child support add-on expenses, and the default is proportional to income, not an even 50/50. If you earn 65% of the combined adjusted net income, you pay 65% of qualifying add-ons like work-related daycare and uninsured medical bills. A different division applies only if a parent asks for one or the court orders it on its own motion.1California Legislative Information. California Family Code 4061
What Section 4061 Governs
Section 4061 does not set the base child support amount. Base support comes from a separate statewide guideline formula that weighs each parent’s net income against the time each parent spends with the children.2California Legislative Information. California Family Code 4055 Section 4061 picks up after that calculation and controls how the extra costs defined in Section 4062 get divided. It is the rulebook for everything beyond the monthly base check.
The underlying principle is that both parents share the duty to support their children according to their circumstances, and that children should benefit from the financial position of both households.3California Legislative Information. California Family Code 4053 Section 4061 carries that idea into add-ons by tying each parent’s share to what they can actually afford.
The Proportional Default, Not a 50/50 Split
This is where older summaries sometimes mislead parents. Section 4061(a) does not create an equal split. The default is that add-on expenses are divided in proportion to each parent’s adjusted net income. If one parent earns 70% of the combined adjusted income, that parent owes 70% of the qualifying add-on costs.1California Legislative Information. California Family Code 4061
Section 4061(b) reinforces the point by laying out the order of operations. The court first calculates basic child support using the statewide guideline formula. Any add-on expenses are then separately divided in proportion to the parents’ adjusted net disposable incomes. The proportional method appears in both subdivisions, which is why it is clearly the intended default.1California Legislative Information. California Family Code 4061
An equal split, or any other division, is possible only if a parent specifically asks for it or the court on its own motion decides a different allocation is appropriate. Without that affirmative step, the income-based proportion controls.
How Adjusted Net Income Is Calculated
The proportional math does not run off raw gross income. Section 4061 requires two specific adjustments that can shift each parent’s share meaningfully.
Spousal Support Adjustment
When one parent pays spousal support to the other, the paying parent’s gross income is reduced by the spousal support amount, and the receiving parent’s gross income is increased by the same amount, for as long as the spousal support order is active and being paid. This keeps the add-on split from ignoring a substantial transfer of income that is already happening between the households.1California Legislative Information. California Family Code 4061
Basic Child Support Adjustment
The parent paying base child support gets their net disposable income reduced by the amount of that basic support obligation. The receiving parent’s net disposable income is not increased by the child support received. This one-sided adjustment recognizes that the paying parent has less money available for additional expenses after the base check goes out, while avoiding the circular logic of treating received child support as income for calculating more support.1California Legislative Information. California Family Code 4061
A Worked Example
Say Parent A has a net disposable income of $8,000 per month, pays $1,500 in base child support, and pays $1,000 in spousal support. Parent B has a net disposable income of $3,000 and receives that spousal support. For purposes of dividing add-on expenses, Parent A’s adjusted income becomes $8,000 minus $1,500 minus $1,000, or $5,500. Parent B’s adjusted income becomes $3,000 plus $1,000, or $4,000. The combined adjusted total is $9,500. Parent A owes roughly 58% of add-on costs, Parent B about 42%.
Which Expenses Get Split This Way
Section 4062 defines two tiers of add-ons that run through the 4061 split. The distinction matters because the court must order the first tier but has discretion over the second.4California Legislative Information. California Family Code 4062
Mandatory add-ons are childcare costs tied to employment or reasonably necessary job training, and uninsured health care costs for the children (medical, dental, orthodontic, vision, prescription). If childcare is already baked into the guideline base calculation, it is not added again.
Discretionary add-ons are educational or special-needs costs such as private school tuition, tutoring, or therapies, and travel costs necessary for visitation. Courts regularly order these when a child has documented needs or when distance between households makes travel unavoidable.
Asking for a Different Split
A parent who wants something other than the proportional default has to raise it. The request can go either direction: a lower-earning parent asking the higher earner to carry more because of hardship, or a parent arguing that an equal split better reflects how the parties handle expenses. The court can also move on its own if the record shows a different allocation is warranted. Nothing happens automatically; silence means proportional.1California Legislative Information. California Family Code 4061
Accurate income data drives the whole calculation, which is why each parent files an Income and Expense Declaration on Form FL-150 with pay stubs from the last two months attached and the most recent federal tax return brought to the hearing.5Judicial Council of California. Income and Expense Declaration
How Reimbursement Actually Works
Getting your share of an add-on expense from the other parent follows strict timelines under Section 4063 and the court’s standard notice form (FL-192). These catch many parents off guard.
Submitting the Cost
A parent who pays for a qualifying expense must send the other parent an itemized statement within a reasonable time, and no later than 90 days after the cost was incurred or billed.6Judicial Council of California. Notice of Rights and Responsibilities Regarding Child Support Missing that window creates enforcement complications, so keeping receipts organized matters.
Paying Your Share
Once you receive notice, you must pay your court-ordered share within whatever timeframe the court set. If no deadline is specified, payment is due within 30 days of receiving notice. The schedule can also follow a health care provider’s billing cycle, a written agreement between the parents, or a payment plan the court adopts.7California Legislative Information. California Family Code 4063
Pay First, Dispute Later
If you think a charge is unreasonable, you still have to pay it and then seek relief from the court. Withholding payment while you argue exposes you to enforcement and potentially an order covering the other parent’s attorney’s fees and filing costs.7California Legislative Information. California Family Code 4063 Childcare and uninsured health care costs actually paid carry a rebuttable presumption of reasonableness, so the burden sits on the parent challenging the expense.
Changing the Split When Income Changes
The proportion is only as current as the income figures behind it. When circumstances change enough that the existing support order would move by at least 20% or $50 (whichever is less), either parent can request a modification.8California Child Support Services. Changing a Child Support Amount That typically means filing an updated FL-150 along with a motion explaining the change. The court then recalculates both the base support and the add-on proportions on the current picture. The add-on allocation can shift even if the base amount holds steady, because any change in one parent’s income redraws the Section 4061 split.