The Basics of Joint Custody and Child Support

If you have joint custody, make sure you know how child support obligations may be affected.

Joint physical custody, when both co-parents share the responsibility of day-to-day care of their child or children, is one of the most common shared parenting arrangements after a divorce or separation. Yet many parents are still in the dark about the ways that joint custody and child support interact. Keep reading if you are looking for clarity about joint custody child support. We help to answer the question of who pays child support in joint custody.

What's in this guide:

Do you pay child support with joint custody?

The short answer is: yes. Shared parenting arrangements that include joint physical custody do not negate child support obligations between parents. But there are many key factors that may affect the amount of child support owed.

When one parent has sole physical custody, typically the other, non-custodial parent will be responsible for making child support payments.

These child support payments help the custodial parent with providing shelter, food, clothing, and other necessities for their children. Learn more about what’s covered by child support in this article.

When physical custody is shared, however, both parents will be providing those basics to their children independently. That fact may lead some co-parents to believe that their state's child support laws will not apply to them, but that's simply not the case.

Certain states do allow judges discretion over when it's appropriate to deviate from the state's child support formulas, and some may choose to do so for situations that involve joint physical custody. But that's not a guarantee and a deviation from standard child support formulas could still involve one parent being responsible for child support payments in some form.


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What affects the amount owed for child support in families with joint custody?

Income Shares vs. Percentage of Income Models

The ultimate goal of child support laws is to ensure that children have access to the same standard of living that they would if both of their parents were living together. Most state child support laws use one of two ways to determine child support obligations. It's helpful to understand which model your state uses because it will affect the calculation of your child support obligations.

Income Shares Model

The income shares model uses the combined monthly income of parents and the number of children to determine child support obligations. Once the child support obligation is determined, the court uses the parents’ proportional contributions to the combined monthly income to divide the obligation between them.

There is a refined version of the Income Shares model, called the Melson Formula, that also takes a parent's ability to meet their own basic needs into account when calculating child support obligations. The Melson Formula is only used by three states: Delaware, Hawaii, and Montana.

Mom and son play on the beach.

Percentage of Income Model

The percentage of income model determines child support obligations by using a percentage rate of a parent's monthly earnings. That percentage can be dependent on the number of children. Certain states have a flat rate that is applied across all income levels. Other states have varying percentage rates that take the obligor's income level into account.

Parenting time

Amount of time affects child custody. Many states have provisions in their child support laws that take the allocation of parenting time into account when calculating child support obligations.

Even parents who do not have an equal 50/50 split in parenting time may see a reduction in their child support payments.

When determining how parenting time should affect child support obligation, courts frequently use the number of overnights each parent has with their children. Many court websites have parenting time calculators or worksheets to help co-parents determine the number of nights each has for a certain year.

Certain states also take 'equivalent care' into account when modifying child support obligations. Equivalent care, which may be referred to by a different term in your state, is time spent with one parent that does not include overnight stays but during which the parent still incurs expenses roughly equivalent to parenting time with an overnight stay.

Dad and daughter smile for a photo in the grass in front of a house.

Parent Income

In certain situations where parents have equal amounts of parenting time and also have roughly equal income, it may be the case that no child support is paid between co-parents. If co-parents come to collaborative custody agreements that no child support is to be paid between them, some courts may be able to accept that agreement if, and only if, they determine that it's in the best interests of the child.

However, if there are differences in income between parents, that will have an effect on the amount of child support owed.

Family law is complicated, and child support laws are even more complicated with many added factors that have the potential to affect the calculations of child support obligations.

It's absolutely vital that parents consult a legal professional and trusted law firm in their area about their own child support issues.

How to Prevent 50/50 Custody?

Sometimes a parent would like to prevent joint physical custody. The most essential aspect of joint custody is that a custody agreement may be modified at any time if one parent can demonstrate a change in circumstances.

Reasons for Not Gaining Primary Physical Custody or Joint Physical Custody

Many courts favor joint physical and legal custody for both parents because it is in the child's best interests to have a connection with both parents.

However, if the sole best interest of the kid is to be given physical custody to a single parent, the court will do so.

For example, if one parent has a history of maltreatment or neglect that might endanger a child or children, shared physical custody may be denied.

Additionally, courts might refuse shared physical custody if one parent has substance abuse or mental health issues that would prevent them from providing adequate care for their kid.

Even if you are granted sole physical custody, the court will continue to work hard to include the other parent back into your child's life by allowing them visitation rights, supervised if necessary, or directing mediation and therapy.

Because it offers a considerably better outcome for the kid, most psychological experts and legal professionals advocate joint custody.

There are a variety of reasons why a parent might not acquire shared physical custody. The following are some examples:

  • Incarceration – if one parent is incarcerated or in jail, they are physically unable to provide a home or care for them.
  • Relocation - If one parent has plans to move from the state or country, the court may find that it is best for that child to stay in sole custody with the parent that is not relocating.

Reasons for Not Gaining Sole Legal Custody

The issues that might prevent a parent from receiving shared legal custody are comparable to those that might prevent them from obtaining shared physical custody.

  • Relocation
  • Mental health issues
  • Domestic violence
  • Ongoing drug or alcohol abuse
  • Child abuse, maltreatment, or neglect
  • Incarceration or jail time

Child Custody is Complex and for Family Law Experts

The most important thing to know about joint custody is that any custody agreement may be altered at any time if one parent files a petition and demonstrates a change in circumstances. Custody is a difficult topic, and the rules differ by state and jurisdiction. If you have concerns about custody, we recommend that you speak with an experienced family law attorney in your region to learn more.


NOTE: Many state and federal laws use terms like ‘custody’ when referring to arrangements regarding parenting time and decision-making for a child. While this has been the case for many years, these are not the only terms currently used to refer to these topics.

Today, many family law practitioners and even laws within certain states use terms such as ‘parenting arrangements’ or ‘parenting responsibility,’ among others, when referring to matters surrounding legal and physical child custody. You will find these terms as well as custody used on the OurFamilyWizard website.