John Buckley and Laura Monroe
According to the federal Family Support Act of 1988, every state (including the District of Columbia) must develop and apply Child Support Guidelines for the calculation of child support obligations. By 1994, each state had established such parameters. Even though they are called “guidelines,” the judges who order child support are in fact required to follow them.
Child Support Models
Each state follows one of three basic models, or formulas, for calculating a child support obligation: (1) the Incomes Shares model, (2) the Percentage of Income model, or (3) the Melson Formula model.
• The Income Shares Model is based on the concept that the child should receive the same amount of parental support that he or she would have received if the parents had continued to live together. This model calculates support as the approximate share of each parent's income that would have been devoted to the child in a shared household. Calculators vary by state but will essentially add the income of both parents together. The amount needed to support each child is then determined using basic parameters and then adding on any additional expenses such as childcare, medical expenses, and so on. Finally, the support obligation is prorated between each parent depending on their proportionate share of the total income.
In other words, if a child’s custodial parent makes $2,000 a month and the noncustodial parent brings in $3,000, once the amount needed to support the child is determined, then the noncustodial parent will assume 60% of that in the form of support obligation, since he or she earns that percentage of the income.
• The Percentage of Income model calculates child support as a percentage of only the noncustodial parent's income. This model assumes that the custodial parent’s support is spent directly on the child. In this type of calculator, the noncustodial parent’s income is determined and then a percentage is applied to that income based on the child support order and any addons and/or deductions relevant to the particular state.
Here, in the same case of a custodial parent making $2,000 and the noncustodial parent earning $3,000, then the percentage ordered within the state of residence is simply taken from that income, adjusted to include childcare and other expenses, and ordered as support. (Note: The District of Columbia and Massachusetts have developed a formula that is a combination, or a hybrid, of the Income Shares and the Percentage of Income models.)
• The Melson Formula is a more complex version of the Income Shares model. One of its special features is a Standard of Living Adjustment (SOLA), which automatically enables the child to share in a parent or parents’ increased income. Essentially, this is a sixstep process which takes into consideration the children’s primary support needs, any child care and extraordinary medical expenses, and the SOLA. These amounts are added together, and then the courts look at each parent’s minimal selfsupport needs and percentage of total net income to determine the support obligation.
Common Adjustments to Child Support Obligations
In some cases, the parents have shared physical custody of the child, which means that the child spends an approximately equal amount of time with each parent over the course of a year. For this circumstance, an adjustment in support is often required to reflect the fact that there is no “custodial” or “noncustodial” parent. Some states allow an offset, or some other adjustment mechanism, to the basic support obligation that takes into account a shared physical custody arrangement.
Other common factors that are considered in the calculation of a child support award are the costs of child care and extraordinary medical expenses. In some states, these costs are deducted from the initial determination of income, while in other states they are treated as a reason to adjust the amount of support dictated by the guideline formula.
The cost of private schooling for the child is often taken into account as well. Some states treat this cost as an additional factor (or addon) in the initial support calculation. Most states, however, treat this cost as a reason to adjust the amount of support.
The following table shows the particular model of support calculation that has been adopted in each state. Addons (where the expense is added into the support calculation) and deductions (whereby the extra expense is taken off the determined support obligation) are indicated as either mandatory or permissive. When a deduction is considered to be a deviation factor, where the court makes an adjustment to the statemandated calculation formula, then that is also indicated.
STATE

Support calculation model

Shared Parenting Offset

Child care deduction

Extraordinary Medical deduction

Private school tuition

Alabama

Income
Shares

x

Mandatory Deduction

Permissive Deduction

Deviation Factor

Alaska

Percent of Income

x

Mandatory Deduction

Deviation
Factor


Arizona

Income
Shares

x

Permissive Deduction

Mandatory Deduction

Permissive
AddOn/
Deviation Factor

Arkansas

Percent of Income

x

Deviation Factor

Deviation
Factor

Deviation Factor

California

Income
Shares

x

Mandatory Deduction

Mandatory Deduction

Deviation Factor

Colorado

Income
Shares

x

Mandatory Deduction

Mandatory Deduction

Permissive
AddOn

Connecticut

Income
Shares


Permissive Deduction

Deviation
Factor

Deviation Factor

Delaware

Melson
Formula


Mandatory Deduction

Mandatory Deduction


District of Columbia

Income Shares/
Percent of Income
Hybrid

x

x

Deviation
Factor


Florida

Income Shares

x

Mandatory Deduction

Permissive Deduction

Deviation Factor

Georgia

Income Shares

x

Mandatory Deduction

Permissive Deduction

Deviation Factor

Hawaii

Melson Formula

x

x

Mandatory Deduction

Deviation Factor

Idaho

Income Shares

x

Permissive Deduction

Mandatory Deduction


Illinois

Percent of Income




Deviation Factor

Indiana

Income Shares

x

Mandatory Deduction

Permissive Deduction

Deviation Factor

Iowa

Income Shares

x

Mandatory Deduction



Kansas

Income Shares

x

Mandatory Deduction


Deviation Factor

Kentucky

Income Shares


Permissive Deduction

Mandatory Deduction

Deviation Factor

Louisiana

Income Shares

x

Mandatory Deduction

Mandatory Deduction

Deviation Factor

Maine

Income Shares


Mandatory Deduction

Mandatory Deduction

Deviation Factor

Maryland

Income Shares

x

Mandatory Deduction

Mandatory Deduction

Deviation Factor

Massachusetts

Income Shares/
Percent of Income
Hybrid


x

Mandatory Deduction

Deviation Factor

Michigan

Income Shares

x

Mandatory Deduction

Mandatory Deduction

Deviation Factor

Minnesota

Income Shares

x

Mandatory Deduction



Mississippi

Percent of Income

x

Deviation Factor

Deviation
Factor

Deviation Factor

Missouri

Income Shares

x

x

x

Deviation Factor

Montana*

Melson Formula


Mandatory Deduction

Mandatory Deduction

Deviation Factor

Nebraska

Income Shares

x

Mandatory Deduction

Deviation Factor


Nevada

Percent of Income

x

Deviation Factor

Mandatory Deduction

Deviation Factor

New Hampshire

Income Shares


x

x


New Jersey

Income Shares

x

x


Deviation Factor

New Mexico

Income Shares

x


Deviation
Factor

Deviation Factor

New York

Income Shares


Mandatory Deduction


Deviation Factor

North Carolina

Income Shares


Mandatory Deduction

Mandatory Deduction

Permissive
AddOn

North Dakota

Percent of Income

x


Mandatory Deduction

Deviation Factor

Ohio

Income Shares

x

x

x

Deviation Factor

Oklahoma

Income Shares

x

Mandatory Deduction

Mandatory
AddOn


Oregon

Income Shares

x

Mandatory Deduction

Permissive Deduction


Pennsylvania

Income Shares

x

Mandatory Deduction

Mandatory Deduction

Deviation Factor

Rhode Island

Income Shares


Mandatory Deduction

Deviation
Factor


South Carolina

Income Shares


Mandatory Deduction

Deviation
Factor

Deviation Factor

South Dakota

Income Shares


Deviation Factor

Deviation
Factor

Deviation Factor

Tennessee

Income Shares

x


Mandatory Deduction

Permissive
AddOn

Texas

Percent of Income


Deviation Factor

Mandatory Deduction

Deviation Factor

Utah

Income Shares

x

Mandatory Deduction

Mandatory Deduction

Deviation Factor

Vermont

Income Shares

x

Mandatory Deduction

Mandatory Deduction

Permissive
AddOn

Virginia

Income Shares

x

Mandatory
AddOn

Mandatory
AddOn

Permissive
AddOn

Washington

Income Shares


Mandatory Deduction

Mandatory Deduction

Deviation Factor

West Virginia

Income Shares

x

Mandatory Deduction

Mandatory Deduction

Permissive
AddOn

Wisconsin

Percent of Income


Deviation Factor

Mandatory Deduction

Permissive
AddOn

Wyoming

Income Shares


Deviation Factor

Deviation
Factor

Permissive
AddOn

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Keywords: child support, guidelines, state by state, state child support