How Child Support Calculations Vary by State

How states in the U.S. calculate child support differently.

• 4 min read
• family law
• finances

How is child support calculated in the U.S.? 

Depending on where you live, child support payments will be impacted by your state’s default formula and either the non-custodial parent’s circumstances or both parents’ financial situations. Even though most of the U.S. follows the same model, each case may be handled differently. 

A judge will typically consider the following factors when calculating child support payments: 

• The number of children supported by the payments 
• Whether any children are involved that are not intended recipients of payments 
• The parents’ custody schedule arrangement 
• Each child’s age 
• How much each parent earns a month 
• Any existing childcare expenses 
• Any exceptional circumstances that require supplementary medical, psychological, or educational care  

After establishing relevant factors that may affect a co-parent’s ability to pay child support, a judge will use one of three models to calculate payment amounts: the income shares model, the percentage of income model, and the Melson Formula. 

Income shares model 

Forty-one states and two territories use the income shares model to calculate child support payments. Using this model, the judge in a state would combine both parents’ gross incomes to determine how much would be available for the child if the parents lived together. Payments are based on the share of the total each parent contributes. 

For example, if one parent makes $5,000 a month and the other makes $10,000 a month, the monthly total available to support the child is $15,000. The share of the income is a third with one parent and two-thirds with the other. Based on this proportion, the parent who makes $5,000 would cover a third of the child’s expenses, and the parent who makes $10,000 would cover the remaining two-thirds. 

If a state dictates in its statute that the base child support obligation is $500 a month, that amount would be prorated between the parents based on their share of the combined monthly income. If the non-custodial parent had two-thirds of the total, the estimated monthly payment would be around $333. If the non-custodial parent had a third of the whole, the monthly payment would be $167. 

Percentage of income model 

The percentage of income model is used in six states and has two variations. The flat version of the model is used in four of the six states and applies the same percentage to a parent’s income regardless of their income bracket. The varying version is used in the remaining two and adjusts payments according to a parent’s income bracket. In either interpretation, only the non-custodial parent’s income is considered in calculating child support payments. 

For example, if a non-custodial parent makes $5,000 a month, and the income owed for child support in that parent’s state is 20% for one child, that parent would make $1,000 payments each month. If the state follows the flat model, it will apply that 20% regardless of the parent’s income. If the state follows the varying model, payments can be adjusted if the non-custodial parent’s income cannot accommodate the 20% rate. 

Melson Formula 

The Melson Formula was developed by the Delaware Supreme Court decision in Dalton v. Clanton in 1989 and is only used in three states. The decision identified three elements that were crucial in the determination of child support in addition to each parent’s income: 

1. Each parent should retain enough income to cover their needs. 
2. Parents can retain income once the basic needs of their child are satisfied. 
3. Any income that exceeds what is needed to provide for the parent and child’s needs will be shared through child support. 

By taking these three points into consideration, the Melson Formula enables judges to determine payment amounts while balancing the child’s needs and each parent’s needs. 

How does each state calculate child support? 

Just as laws related to custody vary by state, child support is regulated at the state level. Depending on the state’s method of determining child support, the guidelines are implemented in statutes, court rules or decisions, or administrative regulation. 

According to the National Conference of State Legislatures, here are the default models used to calculate child support in each U.S. state and some territories: 

Income shares model 

Percentage of income model 

• Alaska (flat) 
• D.C. (hybrid varying) 
• Mississippi (flat) 
• Nevada (flat) 
• North Dakota (varying) 
• Texas (varying) 
• Wisconsin (flat) 

Melson Formula 

• Delaware 
• Hawaii 
• Montana 

Even though these states have specific models for regular implementation in child support cases, a judge in any state can choose to implement an alternate method than the state’s default formula. Because of this potential variability in how payments are calculated, it is best to work with an experienced family law attorney to ensure you have a complete understanding of your case and how child support may be determined in your situation. 

Can child support be enforced internationally? 

Parents often have concerns about how child support works if one parent moves out of the country. According to the Office of Child Support Services, the U.S. government has arrangements with other countries to provide child support services for international parents. These agreements have specific procedures for parents to establish and enforce child support orders even if a parent lives outside the states. In order to determine how your state handles international child support cases, contact your local child support office. 

The following countries have an arrangement with the U.S. to provide child support services: 

How TalkingParents helps with child support 

TalkingParents can help you manage all things co-parenting, including child support payments, in one service. Our Accountable Payments feature allows you and your co-parent to easily keep tabs on all shared expenses related to your child. Every requested, canceled, and completed payment in TalkingParents is timestamped and documented for transparency. We also offer features for co-parents to message, call, manage their child’s schedule, and more in a documented fashion by providing all these interactions on an Unalterable Record. These Records can be accessed by either parent at any time for utilization in court or otherwise. Records can help co-parents feel reassured by keeping every action related to child support payments organized, documented, and presentable as evidence if needed.