Child support is designed to meet children’s basic needs, including food, shelter, clothing etc. It is typically based on:
- each parent’s income
- the amount of parenting time each parent has with the children;
- the children’s needs
Both parents are required to support their children. However, the higher-earning parent will generally be required to pay child support to the lower-earning parent in all divorce and parentage cases. The amount of that support depends on the state's guideline child support formula.
Parents may be able to enter into alternative arrangements that don't require one parent to pay the other for the support of their children, but they can generally only do that if they AGREE on the terms AND if the judge signs off on the agreement.
Not all of your children's expenses are covered by child support. For example, health insurance, medical care, day care costs, private school tuition, extracurricular activity expenses, and other expenses for the children are typically NOT included in child support. A court may (and usually does!) order parents to pay for these expenses in addition to child support.
(If you're not sure which of your children's expenses you may have to pay, check with a good divorce lawyer in your state.)
Child Support in General
Child support is generally paid to the "custodial" parent by the “non-custodial” parent. In states like Illinois, which have abolished the concept of "child custody," child support is paid by the person who is designated as the “supporting parent” in the divorce or parentage judgment.
Child support laws vary from state to state. How much you will have to pay (or will receive) in support depends upon the laws in your state. The way child support is calculated varies from state to state, too. However, every state has some type of formula that's used for calculating child support.

Most states, including Illinois, call their child support calculation formula a "guideline." However, these guidelines are more like rules than ordinary guidelines. Judges rarely deviate from the guideline formulas, although they usually have the power to do so.
Judges will sometimes order a parent to pay more than guideline support if their child needs more money for some reason. For example, a child with special needs may have extraordinary expenses. They may need to be in a private school, or work with private tutors. Or they may need expensive medical care. In those cases, a judge has the discretion to order a parent to pay more in child support than what the guideline formula requires.
On the other hand, guideline support for a very high-earning parent may exceed what their child needs. In high net-worth divorces, the judge may allow the parents to pay less than the guideline support amount.
To figure out whether you have any grounds to deviate from guideline support in your divorce, check with an attorney in your area.

How Is Guideline Child Support Calculated?
Child support guidelines vary from state to state. In most states, child support guidelines are based on both parents’ incomes as well as the amount of time each parent spends with the children. This "time" is usually calculated by counting the number of overnights that children spend with a particular parent. For example, in Illinois, if a child spends 146 overnights or more with a parent, then that parent's support obligation will be reduced.
Child support calculations can be quite complicated. Even when the formula looks simple, if the data used in the formula isn't simple and clear, the amount calculated for support can vary wildly. For example, if a parent owns his/her own business, then his/her personal "net income" depends on their business expenses. Lawyers can argue for days about which "business" expenses are legitimate and which are not.
The same thing is true for parents who are paid bonuses or commissions. All of their income may count for child support purposes. However, how much they should pay from one week to the next can vary dramatically. For that reason, child support is often set based on a parent's base pay. They then pay additional support on their commission or bonus income if, as, and when they receive it.
If you are trying to figure out how much support you will have to pay or will receive, the best way to do it is to contact a good divorce attorney. in your area. However, if you want to get a rough estimate of what child support might be, you can use a child support calculator. (To calculate your support in Illinois, you can use the Illinois Child Support Estimator.)
Paying for Children's College Educational Expenses
Depending on the state you live in (like in Illinois), you may be required to contribute to your children’s college educational expenses. This is in addition to all of the other expenses you are required to pay for your kids before they get to college. The extent of your obligation depends upon the income and assets of both you and your ex, how much money your children have saved for college, and how much money your children earn.

Most states do NOT require divorced parents to contribute to their children's college education expenses. Illinois does.
In Illinois, the amount of a parent's contribution to their children's college education expenses is currently limited to the cost of attending the University of Illinois at Champaign-Urbana.
To determine what your state requires regarding the payment of expenses for the children, check with an experienced divorce lawyer in your area.
