Income shares vs percentage of income: how child support models differ (2026)

States write their child support guidelines in a few main ways. This explainer compares the two best-known models, percentage of income and income shares, using the three states the calculator covers. For how the engine runs each state’s steps, see how child support is calculated.

What is the percentage of income model?

Support is a fixed percentage of the paying parent’s income. The percentage depends on the number of children, and the other parent’s income is not part of the calculation.

Texas is an example. Texas Family Code § 154.125 applies these percentages to the paying parent’s monthly net resources, which are income after federal income tax, Social Security, Medicare and a few other deductions (§ 154.062):

Children	Texas percentage of net resources
1	20%
2	25%
3	30%
4	35%
5	40%

The percentage applies to net resources up to a cap, $11,700 a month. The other parent’s income can still matter: Texas lists the net resources of the parent the children live with among the factors a court considers when deciding whether to depart from the guideline (§ 154.123(b)(5)).

What is the income shares model?

The guideline starts from both parents’ income combined. A schedule gives the basic support amount for the children at that combined income, and each parent is responsible for a share in proportion to their income. The other parent pays their share to the parent the children live with.

Virginia is an example. Code of Virginia § 20-108.2 B contains the schedule, by combined monthly gross income and number of children. Under § 20-108.2 G 1, health insurance and work related child care are added, and the total is divided between the parents in proportion to their gross incomes. In the schedule, the amount rises more slowly than income, so the share of income going to support falls as combined income rises:

Other parent's income a month	1 child	2 children
$2,000	$333.00	$496.33
$4,000	$560.50	$821.00
$6,000	$750.60	$1,094.40
$8,000	$946.67	$1,372.67
$12,000	$1,275.00	$1,838.25
$20,000	$1,868.33	$2,699.17

Where does New York’s formula fit?

New York combines features of both. Family Court Act § 413(1)(c) applies a fixed percentage, like a percentage of income model, but to both parents’ combined income, and then splits the result by income share, like an income shares model:

1. add both parents’ incomes, after the deductions the statute allows;
2. multiply combined income, up to $193,000 a year, by the percentage for the number of children (17% for one child);
3. split the result in proportion to the two incomes.

Below the cap, step 3 undoes step 1: the paying parent’s share comes to the percentage of their own income. Sources label New York’s model differently, so this site describes it by what the formula does rather than by a label. The New York guide walks through it.

Does the other parent’s income change the amount?

This is where the models differ most. The same paying parent, at $6,000 a month with one child, as the income of the parent the children live with goes up:

Income of the parent the children live with	Texas	New York	Virginia
none	$991.37	$941.97	$999.00
$3,000 a month	$991.37	$941.97	$797.33
$6,000 a month	$991.37	$941.97	$710.00

The Virginia rows assume the children spend 52 days a year with the other parent, below the line where Virginia’s shared custody formula starts. Texas and New York do not change because, in Texas, the other income is not in the formula, and in New York, the percentage of combined income split by share equals the percentage of the paying parent’s own income. Virginia falls because the schedule takes a smaller share of a larger combined income, and the paying parent’s share of that amount shrinks.

The three states also start from different incomes: net resources in Texas, gross income less Social Security and Medicare in New York, and gross income in Virginia. The what counts as income explainer compares them.

How do the models treat time with each parent?

The model does not decide this; each state’s statute does.

State	Is parenting time in the formula?	Source
Texas	No. Time of possession and access is a factor a court considers when deciding whether to depart from the guideline.	Texas Family Code § 154.123(b)(4)
New York	No. Extraordinary visitation expenses, and extended visitation that reduces the other household’s costs, are deviation factors.	Family Court Act § 413(1)(f)(9)
Virginia	Yes, once each parent has the children more than 90 days a year.	Code of Virginia § 20-108.2 G 3

The Virginia shared custody guide and the New York shared custody guide go further.

What do all the models have in common?

Federal rules set minimum requirements for every state’s guideline, whatever the model (45 CFR 302.56):

• the guideline amount is presumed correct, and a court can depart from it only with a written or on-the-record finding that it would be unjust or inappropriate, stating the guideline amount;
• the guideline must take into account all the earnings and income of the paying parent;
• it must allow for the basic needs of a parent with a low income, for example through a self-support reserve;
• if it allows income to be imputed, it must consider the parent’s specific circumstances;
• the state must review its guideline at least once every four years.

What this guide does not cover

This guide covers the two main models as Texas, Virginia and New York use them. It does not cover other guideline models or count how many states use each model. The figures are estimates of the guideline amount. A court can order a different amount, and an existing order only changes when it is modified.