Child support is one of the most common — and most misunderstood — issues in family law. Parents often assume the number is arbitrary, or that it depends entirely on which parent the child lives with. In reality, Louisiana uses a structured formula designed to be predictable and fair. This guide walks through how that formula works, step by step, so you can understand where the number comes from.
The Income Shares Model
Louisiana calculates child support using the income shares model. The principle behind it is simple: a child should receive roughly the same proportion of parental income that the child would have received if the parents lived together. Both parents' incomes are combined, the total support obligation is determined from that combined figure, and each parent is then responsible for their share in proportion to their income.
This is different from models used in some other states that look only at the paying parent's income. In Louisiana, both parents' earnings are part of the calculation.
Step 1: Combined Adjusted Gross Income
The starting point is each parent's gross income — wages, salary, commissions, bonuses, self-employment income, and many other sources. Certain items are then subtracted to reach adjusted gross income, such as pre-existing child support or spousal support obligations actually being paid for other children or a prior spouse.
Both parents' adjusted gross incomes are added together to produce the combined adjusted gross income, which drives the rest of the calculation.
Because both incomes go into the formula, an accurate, honest accounting of income from both parents is essential. Missing or understated income leads to an incorrect support number.
Step 2: The Basic Child Support Obligation
Louisiana publishes a schedule of basic child support obligations in the statutes. You locate your combined adjusted gross income on that schedule, cross-reference the number of children, and the schedule gives the basic support obligation — the baseline amount the law expects to be spent on the children at that income level.
That baseline is then divided between the parents according to each parent's percentage share of the combined income. For example, if one parent earns 60% of the combined income, that parent is generally responsible for 60% of the obligation.
Step 3: Adding the Mandatory Add-Ons
The basic obligation is not the whole picture. Several additional expenses are added on top of the baseline and shared between the parents in the same proportion:
- Health insurance premiums attributable to the children
- Work-related childcare costs, such as daycare that allows a parent to work
- Extraordinary medical expenses, including ongoing treatment not covered by insurance
Courts may also account for other expenses, such as the costs of a special or private education when warranted, or extraordinary travel costs related to visitation. These add-ons are why two families with identical incomes can end up with very different support numbers.
"The formula is structured, but the inputs matter. Getting income and add-ons right is where cases are won or lost."
Call (337) 508-2627Step 4: Custody Adjustments
The amount of time each parent spends with the children can change the calculation. Louisiana recognizes different arrangements:
Sole or primary custody
When one parent has primary physical custody, the other parent typically pays their proportionate share of the obligation to the custodial parent.
Shared custody
When the children spend a substantial, roughly equal amount of time with each parent, a shared-custody calculation applies. It accounts for the fact that both parents are directly covering expenses during their time, which can adjust the final amount owed.
Split custody
When each parent has primary custody of at least one of the children, a split-custody calculation is used, essentially running the formula for each household and offsetting the results.
Imputing Income
What happens when a parent is unemployed or underemployed? Louisiana law allows a court to impute income — that is, to base the calculation on a parent's earning capacity rather than actual earnings — when the court finds the parent is voluntarily unemployed or underemployed. This prevents a parent from sidestepping support by quitting a job or taking a deliberately low-paying one. Courts generally do not impute income when the unemployment is genuinely beyond the parent's control, or in certain situations involving the care of a very young child.
When and How Support Is Modified
A child support order is not necessarily permanent. Life changes — jobs are lost, incomes rise, children's needs shift. To change an existing order, a parent generally must show a material change in circumstances since the last order was entered.
Common grounds for modification include:
- A significant, involuntary change in either parent's income
- A change in the custody or time-sharing arrangement
- A substantial change in the children's needs, such as new medical or childcare costs
- A child reaching the age of majority or otherwise no longer being entitled to support
Importantly, you can't simply stop paying or unilaterally change the amount on your own. Until a court modifies the order, the existing obligation stands and arrears can accrue. If your circumstances have changed, the right step is to seek a formal modification. A Lake Charles child support attorney can review your situation and help you file properly.
Louisiana child support follows a defined formula, but the result depends entirely on getting the inputs right — both parents' income, the add-ons, and the custody arrangement. Understanding how the number is built helps you know whether your order is accurate and when it may be time to revisit it.
