Which child support model does my state use?

About 40 states use the Income Shares model including California, Florida, and New York. Texas and Wisconsin use a Percentage of Income model applied to the non-custodial parent's net resources.

Does custody percentage affect child support?

Yes. In Income Shares states, when the non-custodial parent has 40%+ overnight time, courts typically apply a shared custody adjustment reducing the base obligation. Texas does not directly factor custody percentage into its calculation.

What income is included in child support calculations?

Most states count all income sources: wages, bonuses, self-employment, rental income, dividends, disability, and unemployment. Courts can also impute income if a parent is voluntarily underemployed.

What add-on expenses are included in child support?

Common add-ons include health insurance premiums, work-related childcare, unreimbursed medical expenses, and educational costs. These are typically split proportionally by each parent's income share.

Can child support be modified after it is ordered?

Yes, when there is a substantial change in circumstances such as a 15-20% change in income, a custody change, or new children. Most states allow review every 3 years. You must file with the court — informal agreements are not enforceable.

Child Support Calculator

Estimate monthly child support using the Income Shares model (most states) or Texas percentage model. Instant results as you type.

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Non-Custodial Parent Monthly Income

Gross monthly income

Custodial Parent Monthly Income

Gross monthly income

Number of Children

Custodial Parent Time %

% of time with custodial parent

Health Insurance Premium

Monthly premium for children

Work-Related Childcare

Monthly childcare costs

Estimated Monthly Child Support (Income Shares)

$1,595/mo

Base Support$1,300/mo

NCP Income Share59.1%

Combined Income$11,000/mo

Add-ons (ins/care)$295/mo

The income shares model is used by most US states. This is an estimate — consult an attorney for exact figures.

Advanced Calculator

Multi-state formula comparison, custody percentage impact chart, and year-by-year projection with stepdown analysis.

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Your Situation

NCP Annual Income

CP Annual Income

Number of Children

NCP Custody %

Side-by-Side State Comparison

State 1

State 2

California

$1,063/mo

Annual$12,750

ModelIncome Shares (DissoMaster)

Texas

$1,563/mo

Annual$18,750

ModelPercentage of Net Resources

Difference: $500/mo ($6,000/yr) between California and Texas

Top 5 States Comparison

Professional Simulator

Full income breakdown (W-2, self-employment, bonus), multi-child stepdown, what-if scenarios, NPV analysis, and 20-year lifetime projection.

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NCP Income Breakdown — Total: $80,000/yr

W-2 / Salary

Self-Employment

Bonuses

Other Income

CP Income Breakdown — Total: $35,000/yr

W-2 / Salary

Self-Employment

Bonuses

Custody & Add-Ons

Children

NCP Custody %

Health Insurance/mo

Childcare/mo

Extraordinary Exp/mo

Professional Child Support Analysis

$2,344/mo total

NCP Income Verification

Gross income: $80,000/yr

Adjusted (SE add-back): $81,060/yr

Federal tax: −$9,302/yr

SE tax: −$2,119/yr

Net disposable: $5,803/mo

Support Breakdown

Base support: $1,440/mo

Health ins. share: +$209/mo

Childcare share: +$557/mo

Extraordinary: +$139/mo

Total: $2,344/mo

NCP Income Share69.6%

Annual Total$28,132

% of NCP Net40.4%

Multi-Child Stepdown Analysis

2 children remaining: $2,205/mo

1 child remaining: $1,832/mo (−$512/mo savings)

How Child Support Is Calculated

Child support in the United States is determined by state-specific guidelines, but two main models dominate: the Income Shares model (used by about 40 states) and the Percentage of Income model (used by states like Texas and Wisconsin).

Income Shares Model

The Income Shares model assumes that a child should receive the same proportion of parental income they would have received if the parents lived together. Both parents' incomes are combined, a base support amount is determined from a schedule, and then each parent contributes proportionally.

Combined Income = Custodial Income + Non-Custodial Income
Base Support = Table Lookup (Combined Income × Children Count)
NCP Share = Non-Custodial Income ÷ Combined Income
NCP Obligation = Base Support × NCP Share
Final = NCP Obligation + Add-ons (insurance, childcare) × NCP Share

Percentage of Income Model

States like Texas apply a flat percentage directly to the non-custodial parent's net resources. Texas rates are 20% for 1 child, 25% for 2, 30% for 3, 35% for 4, and 40% for 5 or more children, capped at $9,200/month in net resources.

Worked Example — Income Shares

Dad (NCP): $6,500/mo gross. Mom (custodial): $4,500/mo gross. Two children. Mom has 80% custody.

Combined Monthly Income$11,000

Base Support (2 children)$1,672

Dad's Income Share59.1%

Dad's Base Obligation$988/mo

Add-ons (insurance + childcare)$295/mo

Total Monthly Payment$1,283/mo

Frequently Asked Questions

Which model does my state use? ▼

About 40 states use the Income Shares model, including California, Florida, New York, Illinois, and most of the Midwest and South. Texas, Wisconsin, and a handful of others use a Percentage of Income model applied to the non-custodial parent's income only. A few states (like Delaware) use a hybrid. Always verify with your state's child support agency or an attorney.

Does custody percentage affect the support amount? ▼

Yes, significantly. In most Income Shares states, when the non-custodial parent has substantial overnight time (typically 40%+ or 146+ overnights per year), courts apply a shared custody adjustment that reduces the base obligation proportionally. The exact threshold varies by state. In Texas, custody percentage is not directly factored into the percentage calculation.

What income is counted for child support purposes? ▼

Most states include all sources of income: wages, salaries, bonuses, commissions, self-employment income, rental income, interest, dividends, unemployment benefits, disability payments, and Social Security. Some states use gross income, while others (like Texas) use net resources after taxes and certain deductions. Courts can also "impute" income if a parent is voluntarily underemployed.

What add-on expenses are typically included? ▼

Common add-ons beyond basic support include: health insurance premiums for the children, work-related childcare costs, unreimbursed medical expenses, educational expenses, and in some states, extracurricular activity costs. These are usually split proportionally based on each parent's share of combined income.

Can child support be modified after it's ordered? ▼

Yes. Child support can be modified when there is a substantial change in circumstances — typically a change in income of 15-20% or more, a change in custody arrangements, changes in the children's needs, or the birth of another child. Most states allow review every 3 years regardless of changed circumstances. You must file with the court or child support agency; you cannot modify it informally with the other parent.