A Comprehensive Guide on How Child Support is Determined

About Brette Sember, JD | Divorce.com

By Brette Sember, JD Updated Mar 15, 2024


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Child support is payments from one parent to another to ensure that the child's needs are met and that the parents share the cost of supporting the child.

If you are wondering how child support obligations are determined, it is essential to understand that each state has its own laws and specific formula it uses.

However, in general, both parents' incomes are considered, and the parent that spends the least amount of time with the child usually makes payments to the parent the child primarily lives with.

Key Takeaways

  • Child support is determined by state law, and each state has its own statute.
  • Child support is determined by considering various factors, including income and the number of children.
  • Three child support models are used in the U.S.: the income shares model, the percentage of income model, and the Melson formula.
  • Parents can create their own child support agreement, but the judge must approve it.

Legal Framework for Child Support

Each state has its own guidelines for calculating child support. This is a law that states how child support is calculated. The law evaluates the parents's incomes and applies a formula to determine how much should be paid.

To determine how much child support is required in your situation, you must apply your state guidelines to your income to determine how much would typically be ordered.

Keep in mind that child support guidelines differ by state. Therefore, the amount you may be required to pay depends on your state's specific regulations and your individual situation.

How Is Child Support Determined? Key Factors in Calculating Child Support

Child support is determined by a formula set out by each state's laws that evaluates the parents' incomes.

There is usually a minimum amount of child support that can be ordered, and the more children there are, the more support that is required. You can find an online child support calculator for your state to help you calculate child support.

What Does the Child Support Formula Include?


The parents must provide information about their income, which is used to calculate the amount of support. Income includes wages, salaries, bonuses, self-employment income, severance pay, pensions, interest income, investment income, and alimony.

Benefits including Social Security disability, worker's comp, and unemployment are also usually included. Deductions can be taken for taxes, support for other children, union dues, and required payroll deductions.

Other Dependents

If you have other children (from another relationship), you can usually deduct what you pay to support those children.

A new spouse is not considered a dependent you can deduct, even if they do not work. If you and a new partner have children together, your financial circumstances can affect how much child support you must pay.

Parenting Time Factors

In some states, child support is directly tied to the custody arrangements and the amount of overnights the parents have with the child. The more overnight visits a paying parent has, the less child support they owe.

The thinking is that when a child is with you, you are already meeting their needs for that time period and should not have to pay the other parent for needs during that time period. However, this is only true in some states.

Health Care Expenses

In addition to a set amount of child support, health care costs can be divided between the parents. This can include the cost of health insurance premiums for the child and medical expenses not covered by insurance.

Child Care Costs

Child care costs can be added to child support, including nannies, babysitters, after-school care, preschool, and more. These costs are usually allocated between the parents. There may be a requirement that the expenses are necessary to enable the custodial parent to work.

The Child's Age

While the child's age is not taken into account when calculating the amount of child support due, the child's age can impact expenses for which the parents are ordered to share costs.

Children often become involved in sports, extracurricular activities, lessons, and additional classes as they grow. The parents can share these expenses.

In addition to the cost of the activities themselves, parents may be ordered to share the cost of things like uniforms, sports gear, instruments, and supplies.


While each state has a set formula for calculating child support, judges can deviate from the guidelines in situations such as a child with special needs, if the couple has a high standard of living or an extremely high income, travel costs for visitation, or if a parent has a very low income.

If you are seeking a deviation, a family law attorney can help you make your case.

Common Methods of Calculation Child Support

There are three methods of child support calculations used in the U.S. It's essential to understand which one is used by your state.

Remember that these models determine the base level of child support. The costs of health insurance, uncovered health expenses, child care costs, and extracurricular activities can be added to this.

child support calculation models across the US

Income Shares Model

The Income Shares Model is used by 41 states:

Alabama, Arizona, Arkansas, California, Colorado, Connecticut, Florida, Georgia, Idaho, Illinois, Indiana, Iowa, Kansas, Kentucky, Louisiana, Maine, Maryland, Massachusetts, Michigan, Minnesota, Missouri, Nebraska, New Hampshire, New Jersey, New Mexico, New York, North Carolina, Ohio, Oklahoma, Oregon, Pennsylvania, Rhode Island, South Carolina, South Dakota, Tennessee, Utah, Vermont, Virginia, Washington, West Virginia, and Wyoming.

This model ensures that children have the same financial support they would have received if their parents were still together.

To calculate child support under this method:

  1. Determine the total monthly income for both parents combined.
  2. Determine what percent of the total combined monthly income each parent is responsible for (Divide Parent A's income by the total combined income to determine Parent A's percentage).
  3. Check the state guidelines to determine the support amount for the parents' combined monthly income and the number of children.
  4. Multiply each parent's percentage of the earnings (see #2) by the support obligation. That shows how much that parent is responsible for providing.
  5. In a sole custody situation, the non-custodial parent will pay the entire amount determined in #4. If the parents have joint physical custody, then each parent's child support is multiplied by 1.5 (because it costs more to have two households than one). Some states multiply each parent's total by the other parent's percentage of parenting time, and the parent with the highest total then pays the difference between the two.

Here's an example:

  1. Parent A earns $3000 monthly, and Parent B makes $2000. The total income is $5000.
  2. Parent A's income percent is 60% (3000 divided by 5000). Parent B's income percent is 40% (2000 divided by 5000).
  3. The state guidelines say that child support for one child is $1000 per month.
  4. Parent A's share is 60%, so their responsibility is $600. Parent B's percentage is 40%, so their responsibility is $400.
  5. The non-custodial parent pays their share to the custodial parent.

Percentage of Income Model

This model uses a percentage of the non-custodial parent's income to determine child support. The custodial parent's income is not considered.

This model is used in Alaska, Mississippi, Nevada, North Dakota, Texas, and Wisconsin.

To use this model:

  1. Determine the non-custodial parent's income per month.
  2. Refer to the state's child support guidelines to determine what percent of the income is required based on how many children are involved.
  3. Apply that percentage to the non-custodial parent's income.

Here's an example:

  1. Parent A is the non-custodial parent and earns $3000 per month.
  2. The state's child support guidelines state that if there is one child, 20% of that parent's income is due as child support each month.
  3. Parent A will pay Parent B $600 per month.

Melson Formula

The Melson formula is the most complicated child support formula designed to ensure that each parent can meet their basic needs and provide for the children.

Only three states use this model: Delaware, Hawaii, and Montana. Washington, D.C., uses a hybrid variation of this model.

Here's how it works:

  1. Determine the monthly income for both parents.
  2. Refer to the state child support guidelines to determine the self-support reserve for each parent (funds for the parents' basic needs).
  3. Subtract the self-support reserve from each parent's income.
  4. Total the remaining combined monthly income for the parents.
  5. Refer to the child support guidelines to determine the amount of child support that applies based on the number of children and the income level.
  6. Calculate each parent's percent of the combined income (Divide each parent's remaining income by the total combined remaining income).
  7. Multiply the total child support amount by each parent's percentage to determine their responsibility.
  8. The non-custodial parent pays their share to the custodial parent.

Here's an example:

  1. Parent A's monthly income is $3000, and Parent B's is $2000.
  2. The state self-support reserve for each parent is $1000.
  3. The remaining income for Parent A is $2000 ($3000 minus $1000), and for Parent B, it is $1000 ($2000 minus $1000).
  4. The total combined remaining monthly income is $3000.
  5. The child support guidelines state that the amount of child support at this income level for one child is $900.
  6. Parent A's child support percentage is 66.7% ($2000 divided by $3000). Parent B's percentage is 33.3% ($1000 divided by $3000).
  7. Parent A's share is about $600 (66.7% multiplied by $900). Parent B's share is about $300 (33.3% multiplied by $900).
  8. The non-custodial parent pays their share to the custodial parent.

Child Support Agreements and the Guidelines

Each state sets out its own laws about child support, and if you go to court to litigate child support, the guidelines will be applied to your case. You have the option of coming to your own agreement about child support.

You and the other parent can create a fair agreement and submit it to the court. The court may only accept it if the judge believes it is fair or consistent with the guidelines.


Is Child Support Based on Gross Income or Net Income?

To calculate child support, each parent's gross income must be determined. Deductions are taken for things like taxes, union dues, and more.

Do Judges Consider Living Expenses When Calculating Child Support?

Most states do not consider the parents' living expenses when establishing child support; however, states that use the Melson formula do set aside a self-sufficiency reserve for each parent to use for living expenses.

Is Child Support Determined by Potential Earnings Instead of Actual Income?

Child support is usually based on actual income; however, if a parent is intentionally unemployed or underemployed to avoid paying child support, the judge can impute or assign additional income to that parent to make up for the income they have avoided.

What Is a Cost-of-Living Adjustment (COLA) Clause for Child Support?

Some courts include a cost-of-living adjustment (COLA) clause in child support orders.

This clause changes the amount of child support due each year in accordance with increases or decreases in the cost of living. Usually, the Consumer Price Index is the reference point for determining if there has been a change.

If the order does not contain a COLA clause, COLA adjustments to child support payments can be made through modification requests.

Can Judges Decide to Deviate From the Guidelines?

Judges have discretion to deviate from child support guidelines when they believe it is reasonable to do so and is in the child's best interests.

Some of the factors a judge might consider in doing so include:

  • The child's special needs
  • A parent's very high income
  • A parent's very low income
  • If travel is required for visitation/parenting time

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