Child support amounts are set by state law, not by what either parent wants to pay

The amount you pay or receive in child support depends on your state's formula, your income, and how much time each parent spends with the child. There is no single national number. A parent earning $50,000 a year in one state might pay $400 monthly; in another state, $600. The court or child support agency calculates this using guidelines that are public but vary significantly.

Most states use one of three methods: the income shares model (the most common), the percentage of income model, or the combined income model. Each produces different numbers from the same two incomes. Your state's child support agency or the court handling your case will apply whichever method your state uses.

The calculation also accounts for custody time. If both parents share custody roughly equally, the payment is usually lower than if one parent has the child most of the time. Some states adjust for health insurance costs, childcare expenses, and other children the paying parent supports.

Key Takeaways

  • Child support amounts are determined by state law formulas, not by agreement between parents, and vary widely by state and income level.
  • The paying parent's income, the receiving parent's income, and the amount of time each parent spends with the child all affect the final amount.
  • Most states publish their child support guidelines online, so you can see the formula your state uses before a court order is issued.
  • Child support can be modified if either parent's income changes significantly or custody arrangements change.
  • The state enforces child support orders through wage garnishment, tax intercept, and other collection methods if payment stops.

How states calculate the monthly payment

The income shares model, used by most states, works like this: both parents' incomes are added together to find a combined income level. The state guideline then says what percentage of that combined income goes to child support. That total is then split between the parents based on what percentage each parent earns of the combined income. If one parent earns 70% of the combined income, they pay 70% of the child support obligation.

The percentage of income model, used by a smaller number of states, skips the combined step. It takes the paying parent's income alone and applies a flat percentage: typically 17% for one child, 25% for two, 29% for three, and so on. This method is simpler but does not account for the receiving parent's income.

The combined income model adds both parents' incomes and applies a percentage to the total, then divides the result based on custody time. This is less common than the income shares model but produces similar results.

All three methods start with "gross income," which usually means income before taxes. Some states include bonuses, overtime, and self-employment income; others do not. Some states cap income at a certain level (for example, $150,000 annually) to prevent extremely high payments. Your state's child support guidelines document will specify what counts as income and what does not.

What income counts and what does not

Gross wages and salary always count. So do bonuses, overtime, and commissions if they are regular or recurring. Self-employment income counts, but you subtract legitimate business expenses first. Rental income, investment income, and retirement distributions usually count.

Unemployment benefits, Social Security, and disability payments are treated differently depending on the state. Some states include them; others do not. Child support received from another child is usually subtracted. Income from a new spouse or partner does not count toward the paying parent's obligation.

Seasonal work and irregular income are averaged over a year or a longer period to smooth out months with no pay. If you are unemployed or underemployed, the court may use your earning capacity (what you could earn if you worked full-time) rather than your actual income, though this varies by state and circumstance.

How custody time affects the amount

If one parent has the child 100% of the time and the other has no overnight visits, the payment is straightforward: the paying parent's obligation is calculated at full strength. If the parents split time more evenly, the calculation adjusts. Most states reduce the paying parent's obligation if they have the child overnight at least 30% of the time, though the exact threshold varies.

Some states use a "parenting time adjustment" that reduces the paying parent's obligation dollar-for-dollar as their overnight time increases. Others use a formula that accounts for both parents' incomes and custody time simultaneously. A few states do not adjust for custody time at all, which means the parent with less time still pays the full calculated amount.

Custody time is measured in overnights per year or per month, depending on the state. Weekends, school breaks, and summer vacation all count. If custody is not yet formalized by a court order, the state will use whatever arrangement currently exists.

Additional costs beyond the base payment

The base child support amount covers food, housing, and general living expenses. But the court can order additional payments for specific costs. Health insurance premiums for the child are almost always added on top of base support. Childcare expenses required so the receiving parent can work are typically added as well. Uninsured medical and dental expenses are sometimes split between parents or added to the paying parent's obligation.

College expenses are handled differently by state. Some states require parents to contribute to college costs; others do not. If your state does, the amount is usually determined separately from the base child support order, either by agreement or by the court.

If the child has special needs or significant medical expenses, the court may order a higher payment or a separate agreement to cover those costs. These additions are not automatic; they must be requested and approved by the court or agreed to in writing by both parents.

How to find your state's specific formula and amounts

Every state publishes its child support guidelines, usually on the state's child support agency website or the court system website. Search "[your state] child support guidelines" to find the document. The guideline will show you the income table, the percentages used, and any adjustments for custody time or other factors.

Some states provide online calculators where you enter both parents' incomes and custody time and the calculator produces an estimated amount. These are not binding, but they give you a rough idea before you go to court or meet with the child support agency. Be aware that the calculator may not account for all factors a judge would consider.

If you are working with a child support agency or attorney, they will run the calculation for you using your actual income documentation. If you are doing this on your own, the guideline document and calculator are your starting point. Keep in mind that the court can deviate from the guideline amount if there are unusual circumstances, though the judge must document the reason in writing.

What happens if income changes

Child support orders are not permanent. If either parent's income changes significantly—a job loss, a major raise, a career change—either parent can request a modification. Most states allow a modification if income has changed by 10% or more, though the exact threshold varies. A modification request goes back to the court or child support agency that issued the original order.

The paying parent must request the modification; it does not happen automatically. If you lose your job, you should file for modification right away. If you do not, you remain legally responsible for the full amount even if you cannot pay it. Falling behind on payments can result in wage garnishment, tax intercept, and other enforcement actions.

The receiving parent can also request a modification if their income decreases or if the paying parent's income increases. The modification is usually effective from the date the request is filed, not retroactively to when the income change occurred, though some states allow back pay in certain situations.

How child support is collected and enforced

Child support is usually collected through wage garnishment, meaning the amount is deducted from the paying parent's paycheck before they receive it. The employer sends the money to the state's child support agency, which forwards it to the receiving parent. This is the most reliable collection method.

If the paying parent is self-employed or does not have a regular employer, payment is typically made directly to the child support agency or to the receiving parent. If payments fall behind, the state can intercept tax refunds, seize bank accounts, place a lien on property, or suspend a driver's license or professional license. Some states also report arrears to credit bureaus.

If the paying parent cannot pay the full amount, they should contact the child support agency to discuss options. Some agencies offer payment plans or temporary reductions. If you ignore the order and do not pay, enforcement actions will follow, and you may face contempt of court charges.

Frequently Asked Questions

Can child support be modified if my income goes down?

Yes. If your income drops significantly, you can file for a modification with the court or child support agency. You will need to provide proof of the income change, such as a termination letter or recent pay stubs. The modification is usually effective from the date you file, not retroactively, so it is important to file as soon as your income changes.

Does child support end when the child turns 18?

In most states, yes, but the rules vary. Some states extend support until age 19 if the child is still in high school. A few states require support through college if the child is enrolled full-time. The original court order will specify the end date. If you want support to continue past 18, you must request it before the child reaches 18.

What if the paying parent refuses to work to avoid paying child support?

The court can impute income, meaning it assigns an income level based on what the parent could earn if they worked full-time. This is not automatic; the receiving parent must request it and provide evidence that the paying parent is intentionally underemployed. The court then calculates child support based on the imputed income rather than actual income.

Can parents agree to a different amount than what the guideline says?

Yes, but the court must approve it. Parents can negotiate a child support amount that differs from the state guideline, but they must put the agreement in writing and submit it to the court. The judge will review it to make sure it is not unfair to either parent or the child. If the judge approves it, the agreement becomes the court order.

Is child support the same as alimony or spousal support?

No. Child support is for the benefit of the child and is based on the child's needs and both parents' incomes. Spousal support or alimony is paid by one ex-spouse to the other and is based on different factors, such as the length of the marriage and each spouse's earning capacity. They are calculated separately and can both be ordered in the same case.