Child Support Formulas
All states use one of three formulas to calculate child support obligations in divorce. Nine states and the District of Columbia use variations of the percentage of obligor's income model -- a flat percentage is taken from the non-custodial parent's income based on the number of children he is supporting. Most states use the income shares model, a complicated calculation that includes both parents' incomes and the amount of time the children spend with each. Three states -- Hawaii, Delaware and Montana -- use a sophisticated, even more complicated version of the income shares model. In all cases, the court applies one of these formulas to determine how much child support the non-custodial parent should pay when you file for divorce. If you want to set your own child support provisions in your decree, you should still run these calculations on your own first to determine what the court would order if you and your spouse can't reach an agreement. Most states have worksheets available on their websites to help you figure it out.
Deviating by Agreement
Not all families are identical, and child support guidelines are uniform so they might not apply to your personal situation. Some states, such as Maryland and California, allow parents to agree to a different amount based on their unique circumstances. If you and your spouse reach an agreement, you might be able to simply include the number in a marital settlement agreement, which would provide the terms for your decree. In Maryland, you can make a notation on the child support calculations worksheet you must include with your initial divorce paperwork, explaining your reasons for wanting the court to set support in a different amount. Otherwise, you might have to formally submit your request to the court, such as by filing a motion. A judge must approve the change -- it's not automatic.
A judge might not be inclined to approve your agreement if certain conditions exist. For example, you can't deviate from child support guidelines in California if either parent is receiving public assistance or has even applied for it. You must also attest that you know how much your child support obligation would be according to the guidelines -- what the judge would order if you hadn't reached an agreement. You must also typically provide a good reason why you want to deviate from the guidelines. For example, if you think the state's calculations are awfully high so you and your spouse decide on your own to lower the amount, the court probably won't sign off on this. If you and your spouse plan to live in separate and distant counties, however, it's probably going to cost you additional money for transportation so you can see your children. The court would probably agree to lower your support obligation for this reason.
As the custodial parent, you generally can't just request a higher amount of child support on your own and anticipate that a judge will approve it over your spouse's objections. Likewise, as the non-custodial parent, you can't request a lower amount and expect that the judge will just go along with this if your spouse disagrees. If you feel strongly that the guidelines amount of child support is wrong or unfair under your particular circumstances, but your spouse doesn't agree, you can file a motion or petition with the court to address the situation. For example, you may be paying the mortgage on the marital home where your spouse and your children are living. Child support calculations include the cost of providing shelter for your children, so you would effectively be paying this twice unless the guidelines amount was modified. If you and your spouse are not on the same page and can't reach an agreement, a different amount of child support comes down to the opinion of the judge.