Child Support Maryland Joint Custody: How is Child Support Calculated? By Law Office of Robert Castro, P.A. | July 23, 2025 Share When a Maryland couple with minor children seeks a divorce, the Maryland divorce court will award custody and also order child support payments. Generally, child support is the joint obligation of both parents. By statute, there is a formula that must be used by Maryland divorce courts to determine how much child support is required from the parents. These are commonly called the “Guidelines.” For parents whose combined monthly income is $30,000 or less, the use of the Guidelines is mandatory unless there are circumstances that would make use of the formula unjust or inappropriate. If the divorce court deviates from the Guidelines, the court must make specific findings supporting such a deviation, including an explanation of how the deviation serves the best interests of the child. The best interests of the child is the legal standard for decisions made by a Maryland divorce court regarding child custody and child support matters. Now, in cases where physical custody is awarded solely to one parent, the formula involves three factors, which are: The number of children — the higher the number of children, the higher the child support The combined income of the parents Each parent’s percentage of that combined income The Guidelines are consulted. The number of children and the combined parental income are listed in a table with a grid pattern. Cross-referencing joint income and the number of children locates a box containing a number. That number represents what Maryland lawmakers believe is the total amount of child support that the parents should jointly pay for the support of the number of children involved. For ease, let’s say the amount in the box is $3,000 per month and that neither parent has other children to support. In this scenario, each parent will “pay” child support per their percentage of the total income. Let’s say one parent has 66.7% of the total income and the other has 33.3%. Under those circumstances, one parent will pay $2,000 and the other will pay $1,000. However, the parent with sole custody will “pay” by providing housing, food, clothing, entertainment, etc. The non-custodial parent will “write a check.” MD. Fam. Law Code, § 12-204(l). By contrast, when a Maryland divorce court orders joint custody, the formula is more complicated because each parent will be “paying” by providing housing, food, clothing, entertainment, etc. Another name for joint custody is “shared physical custody,” and this exists if one parent keeps the child or children overnight for more than 25% of the year. Md. Fam. Law Code, § 12-201(o). Where custody is shared, the formula for child support payments is the same as described above, but an extra step is taken. That extra step is to multiply each parent’s share of the total child support “… by the percentage of time the child or children spend with the other parent…” Md. Fam. Law Code, § 12-204(m). Using the example from above, assume the parent paying $2,000 a month has the kids for one-third of the overnights. In that hypothetical, the $2,000 is multiplied by the other parent’s two-thirds (which is 0.6666), which lowers the child support “write a check” payment to about $1,320. Contact Waldorf, Maryland Family Law and Child Custody Lawyer Robert Castro Today This article has been provided by the Law Office of Robert Castro. For more information or questions, contact our office to speak to an experienced Maryland family law and divorce lawyer at (301) 870-1200. We are Waldorf, MD, Family Law lawyers. Our address is 2670 Crain Highway, Waldorf, MD, 20601.