There isn’t one national number for how much child support is for two kids, because each state runs its own formula and the result depends on both parents’ incomes, the custody schedule, and the children’s specific costs. As a rough benchmark, states that calculate support from the paying parent’s income alone usually land somewhere between 20% and 33% of that parent’s earnings for two children. States that combine both parents’ incomes spread the obligation proportionally, so the dollar figure moves with the combined household picture rather than tracking a fixed percentage.
The Three Formulas States Use
Which formula your state uses is the single biggest factor in what the order will say.
Income Shares
About 40 states use the Income Shares model. The court adds both parents’ gross incomes, looks up the combined figure on a state table that estimates what a family at that income level spends raising two children, and divides that obligation between the parents in proportion to what each earns. A parent responsible for 65% of the combined income covers 65% of the calculated support figure. The parent with less parenting time typically writes the check, on the assumption that the custodial parent already spends their share directly on the kids.
Percentage of Obligor Income
Six states ignore the custodial parent’s earnings and calculate support as a straight percentage of the non-custodial parent’s income. Four apply a flat percentage at every income level; two use a sliding scale that drops as income rises. For two children, the percentage in these states generally runs 25% to 33% of the paying parent’s income, though states differ on whether the calculation starts from gross or net earnings.
Melson Formula
A few states use the Melson Formula, which builds in a self-support floor. Before any money goes to child support, each parent is allowed enough income to cover their own basic housing, food, and transportation. Only income above that floor feeds the child support calculation, which then works similarly to Income Shares and allocates the remainder proportionally.
What the Court Counts as Income
Courts pull from a wide definition of income. Wages and salary are the starting point, but the calculation also captures bonuses, commissions, overtime, self-employment profits, rental income, dividends, pensions, and some government benefits. The goal is to reflect the parent’s actual economic capacity, not just what a pay stub shows.
Income can also be imputed. If a court finds that a parent is voluntarily unemployed or deliberately underemployed to lower a support obligation, it can calculate support based on what that parent could reasonably earn, using their work history, education, professional qualifications, and local job market. A parent who leaves a $90,000 position for part-time work at a coffee shop will likely see the order built on something closer to the $90,000 figure.
How Custody Changes the Number
One Parent Has the Kids Most of the Time
When one parent has primary physical custody, the other pays a single monthly amount calculated under the state formula. Two children produces a higher figure than one because the state’s cost tables reflect the added expense of a second child.
Shared Parenting Time
Joint physical custody complicates the arithmetic. Most states adjust the base support figure once the non-custodial parent’s overnight count crosses a threshold, often somewhere in the range of 90 to 110 overnights per year, with wide variation from state to state. The reasoning is that a parent who has the children 40% of the time is already covering groceries, utilities, and a bedroom during those nights. Even in a true 50/50 split, the higher-earning parent usually still owes something to keep the children’s standard of living roughly equal between the two homes.
One Child Each
Split custody comes up specifically in two-child families: each parent has primary physical custody of one child. The court runs the formula in both directions, calculating what Parent A owes Parent B for the child living with Parent B, then what Parent B owes Parent A for the child living with Parent A. Whoever owes more pays the difference. Because the two obligations partially cancel, the net payment is often smaller than a traditional sole-custody order would produce.
Health Insurance, Medical Bills, and Childcare
Federal law requires every child support order to address health insurance. When a court or state agency issues a Qualified Medical Child Support Order, the paying parent’s employer-sponsored group health plan has to enroll the children as long as the order meets federal requirements for identifying them and describing the coverage period.
Beyond premiums, most states require parents to share out-of-pocket medical costs that insurance doesn’t cover. Some states divide unreimbursed medical expenses in the same income-based proportion as the base support figure. Others set a threshold, such as $250 per child per year, and only require sharing above that amount. Work-related childcare and extraordinary expenses like tutoring for a child with special needs are also commonly added into the order, on top of the base support number.
Changing the Amount Later
A support order isn’t fixed for life. Either parent can ask the issuing court or state agency to modify it, but the requesting parent has to show a material change in circumstances significant enough to make the current order unreasonable. Common qualifying changes include a substantial rise or drop in either parent’s income, an involuntary job loss, a child developing new medical needs, or a shift in the custody schedule.
Some states also allow a review after a set period, often three years, or when a parent’s income moves by a certain percentage, commonly 15% or more. The process starts with a petition, followed by an exchange of updated financial documents. If the parents can’t agree, a hearing lets both sides present evidence before a judge decides. Whatever formula produced the original order is run again with the current numbers.
A parent who genuinely can’t pay should file for modification immediately instead of simply stopping payments. Non-payment and a pending modification request are treated very differently.
When Support for Two Children Ends
In most states, support for each child ends when that child reaches the age of majority, which is 18 in most jurisdictions. Many states extend the obligation if the child is still enrolled in high school full-time at 18, continuing until graduation or age 19, whichever comes first. A few states run support through age 21 or beyond if the child is in college.
With two children, the obligations don’t automatically end together. Once the older child ages out, the order should be recalculated downward to reflect one remaining child. That recalculation usually isn’t automatic. The paying parent typically has to file a modification request, and until the order is formally changed, the original amount stays enforceable and keeps accruing.
Support also ends earlier if a child marries, joins the military, or is legally emancipated. Going the other way, if a child has a physical or mental disability that prevents self-support and the condition began before age 18, many states let a court extend support indefinitely. The rules for adult-child support vary significantly by state, so parents whose child may qualify should check their own state’s law well before the child approaches adulthood.