How the income shares model works
The income shares model works in three moves: combine the parents’ incomes, read the basic obligation for that income and number of children from a schedule, and divide it by each parent’s share of the combined income.[2]
- Combine. Add both parents’ incomes, gross or net depending on the state.
- Look up. The schedule gives the amount an intact family with that income would be expected to spend on the children.
- Divide. Each parent owes the amount times their share of combined income. The parent the children live with mostly is presumed to spend their share directly; the other parent pays theirs as child support.
- Adjust. Add child care and health insurance, adjust for parenting time, and apply a self-support reserve for low incomes.
Example from North Carolina’s 2023 schedule: combined gross income of $6,000 gives $1,010 a month for one child. A parent earning $4,000 of that has a 66.67% share and owes $673.33 before add-ons.[4]
Schedules compared at $6,000 of combined income
Income shares schedules differ by state because each is built from that state’s chosen economic data and updated on its own calendar; at $6,000 of combined monthly income, the one-child amount ranges widely.[3][4][5][6][7][8]
| State | Income | Schedule since | 1 child | 2 children | 3 children |
|---|---|---|---|---|---|
| Georgia | gross | July 2024 | $1,009 | $1,523 | $1,826 |
| North Carolina | gross | Jan. 2023 | $1,010 | $1,524 | $1,826 |
| Ohio (yearly ÷ 12) | gross | June 2023 | $946 | $1,377 | $1,377 |
| Florida | net | Jan. 2011 | $1,121 | $1,737 | $2,175 |
| Pennsylvania | net | Jan. 2026 | $1,186 | $1,774 | $2,107 |
| Illinois | net | Mar. 2026 | $1,211 | $1,808 | $2,142 |
The net-income schedules (Florida, Pennsylvania, Illinois) are not directly comparable with the gross-income ones: $6,000 of net income corresponds to a higher gross income. Within each state, child support for 2 kids is about 50% higher than for one child, not double.
Income shares vs. percentage of income
The difference is whether the other parent’s income matters: income shares uses both incomes, while a percentage-of-income state uses only the paying parent’s.[2]
| Income shares | Percentage of income | Melson formula | |
|---|---|---|---|
| Whose income | Both parents | Paying parent only | Both parents |
| Basic amount from | Schedule of combined income | Fixed or sliding percentage | Basic needs table plus a standard-of-living share |
| Low-income protection | Self-support reserve in most states | Lower percentages or reserve | Built in: each parent keeps a reserve first |
| States (Dec. 2025) | 44, e.g. FL, GA, IL, NC, OH, PA | 3: Texas, Mississippi, North Dakota | 3: Delaware, Hawaii, Montana |
Labels are not perfectly consistent: New York calls its percentage of combined income an income shares model, and Alaska, Nevada and Wisconsin use percentages for primary custody but are counted as income shares because both incomes are used in shared custody.[2] See the Texas child support calculator for a pure percentage-of-income state.
Why most states use income shares
Federal law requires a guideline but leaves the model to each state; in the 2016 rule HHS also encouraged income shares states to take the custodial parent’s income into account.[1] The income shares approach aims to give children the share of income they would have received if the parents lived together, which is why both incomes and a schedule of typical spending are used.[2]
For the full step-by-step method, read how child support is calculated, or run your own numbers with the child support calculator by state.
General information. Each state’s statute, rules and schedule control. Not legal advice; see our legal disclaimer.
Frequently asked questions
What is the income shares model?
A child support model in which both parents’ incomes are combined, a state schedule gives the amount spent on children at that income, and each parent pays their percentage share.
Which states use the income shares model?
44 states as of December 2025, including California, Florida, Georgia, Illinois, New York, North Carolina, Ohio and Pennsylvania. Texas, Mississippi and North Dakota use a percentage of income; Delaware, Hawaii and Montana use the Melson formula.
How much more is child support for 2 kids than for 1?
In income shares schedules, about 50% more at middle incomes (for example $1,523 instead of $1,009 at $6,000 in Georgia); in Texas, 25% of net resources instead of 20%.
Does the custodial parent pay under income shares?
Their share is presumed to be spent directly on the children, so they do not make a payment. In shared custody, either parent may end up paying the difference.
Sources
- Flexibility, Efficiency, and Modernization in Child Support Enforcement Programs; Final Rule, 81 FR 93492
- Texas Child Support Guidelines Review Report 2025 (national inventory of guideline models, pp. 13–18)
- SB 454 (2024), as passed: amends O.C.G.A. § 19-6-15 (new table; parenting time and low-income adjustments)
- Schedule of Basic Support Obligations (AOC-A-162, Rev. 1/23)
- Section 61.30, Florida Statutes: child support guidelines
- Pa.R.Civ.P. 1910.16-3, Basic Child Support Schedule
- 2026 Illinois Schedule of Basic Obligations
- JFS 07767, Basic Child Support Schedule (Rev. 6/2023)