Child custody is an issue primarily handled by state courts, following state laws. So every state, even every county and city, will be a little bit different. There are some basic child custody rules that apply in pretty much any situation, though.
The best interest of the child
The most important rule to remember is while learning about the child custody rules that courts will make all their decisions in an attempt to protect the best interests of the child.
You usually cannot get a divorce until you have resolved all issues related to children, because the child is being protected regardless of what the parents do.
That means that while the wishes of the parents are important, they can be disregarded. If a judge decides that a child should stay with mom full time to be close to a school that is what the judge will order, even if the parents have decided to split custody more evenly.
Courts will almost always award joint legal custody. This is often borderline required by state law. Utah, for example, has a “rebuttable presumption” favoring joint custody. That means joint custody is assumed unless one parent provides a reason for not having joint legal custody.
So both parents will have an equal say in the major decisions related to the child’s upbringing. For example, both parents will have to agree on what church or school a child will attend. If one parent wanted to get the child into Satanism and the other parent objected, then they may have to go to court to settle the dispute.
Courts do not like to be pulled into ongoing family squabbles, but they will weigh in on major issues like that sometimes.
Physical custody can be handled an infinite number of ways. Many states, like California, encourage parents to submit a joint “parenting plan” to the court. In most cases, the judge will only briefly review this plan and then approve it in an order if there are no red flags suggesting it is not in the best interest of the child.
If the parents cannot propose a plan the judge will have to make one up.
Parents generally get equal time with their children, though that is not always true. Sometimes a child will live with one parent through the school year and another for the summer. Or a child will live primarily with one parent and just spend every other weekend with the other parent.
For roughly equal splits, perhaps the most common is going back and forth every week or every other week. Sometimes parents like to break up the long stretches and have one midweek overnight on weeks where the child is with the other parent. Alternating every three or four days is also popular.
Breaking the custody order can be kidnapping
Sometimes parents will get in a fight and decide to keep a child longer than what is allowed in their order or agreement. This is usually a huge mistake and violates a major child custody rule.
Violating a court order can result in punishment, including jail time. Worse, taking a child out of the other parent’s rightful custody can be kidnapping and parents have been found guilty and punished criminally.