How Child Support Is Calculated

  • There are several different models used to calculate child support across the country
  • The basic formulas are usually fairly simple, though many additional factors can influence the final amount
  • Contact an attorney to review your case for an approximation or if you feel your child support payments are too high
child support

Child support is an area that can be tricky and difficult to understand when it comes to divorce. This is also a part of the process where many non-custodial parents — who are typically fathers — feel they have been treated unfairly by the courts when the support amount seems far too high.

One of the biggest things to keep in mind is that the formulas used by courts are both fairly simple and very complicated at the same time. You must understand that each person’s situation is unique, so there may be certain factors that weigh into the obligation that do not apply to everyone.

Judges are also given the discretion to deviate from the formula for their state to account for unique circumstances.

Since the statutes that govern child support calculations vary, it is crucial to research how child support is handled in the jurisdiction of your case to understand how the total is determined.

The two primary methods used by states to calculate child support are the Income Shares Model and the Percentage of Income Model, though the exact details and numbers that go into the formula will depend on where you live.

child supportHere is a general description of how each model determines the amount of child support you must pay.

Income Shares Model

The majority of states follow the Income Shares model for child support calculations, which attempts to proportionally divide what it costs to raise a child based on the income of both parents.

To simplify how this formula generally works, courts will determine the amount it would take per month to raise a child, add the incomes of both parents together and then figure out what each parent would owe based off their contributions to the total amount.

For example, if a court determined that it would cost $800 per month to raise one child, and the combined income is $80,000 — father makes $50,000 and the mother makes $30,000 — the father would be on the hook for $500 and the mother would be appointed a total of $300.

Basic formula


  1. 50,000 ÷ 80,000 = .625
  2. 800 x .625 = $500


  1. 30,000 ÷ 80,000 = .375
  2. 800 x .375 = $300

Whichever parent receives physical custody would then be awarded the determined amount from the other parent while keeping their portion to be spent on the child.

This method attempts to award a figure based on what the parents would assumedly be contributing if they were still living together in a married household.

Additional factors may also come into play, such as the number of children being supported, extraordinary medical expenses, child care expenses and the custody arrangement itself.

Since joint custody is a fairly common arrangement, the amount of time with the child could play a significant role in the formula. The more overnights you are granted with the child, the lower your support amount could potentially be.

However, this is not always the case, so speak with a local attorney to determine the factors that are involved with your specific case and the laws in your state.

(A modified version of the Income Shares Model is used in Delaware, Hawaii and Montana — known as the Melson Formula — which includes additional factors in an attempt to ensure each parents’ basic needs are met as well as those of the children).

For an example of what a child support formula looks like in an Income Shares state, see Pennsylvania Rules of Civil Procedure 1910.16-4.

Cordell & Cordell understands the concerns men face during divorce.

Percentage of Income Model

The second most common formula used to determine child support amounts is the Percentage of Income model, which uses only the income of the non-custodial parent in the determination of an award.

This method takes the income of the obligor and attributes a percentage that will be taken out as child support based on state factors.

For example, a couple splits where both parents make $35,000 per year, but the mother is awarded primary physical custody. The state’s statutes require that 18 percent of the obligor’s income be awarded to the custodial parent, so the father would be required to pay $525 per month.

Basic formula


  1. $35,000 x .18 = $6,300
  2. $6,300 ÷ 12 = $525

While much simpler on the surface in simply taking a base percentage of income (barring additional factors potentially imposed by the state), it may not necessarily be the “fairest” formula.

This method also may or may not take into consideration the custody arrangement depending on where you live, so again, it is crucial to discuss with an attorney exactly how child support is calculated in the jurisdiction of your case.

For an example of how the child support formula looks in a Percentage of Income state, see section 154.125 of the Texas Family Code.

These outlines give just the basic idea of how child support is calculated, as all of the internal factors and variables are different in each state.

Most states will also periodically review the amount being paid, and you can usually file to modify child support if there is a significant change in circumstances since the original order was issued, such as a change in the custody arrangement, losing a job, etc.

While there are plenty of child support calculators out there to help you estimate the amount of your obligation, you cannot be certain what the amount will be until the judge hands down a ruling.

Contact an attorney to review your case if you are worried the child support you are paying is too high, or if you would like a more accurate approximation of what the costs may be following a divorce in your state.

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