Child Support Calculator – Estimate Monthly Payments
Estimate monthly child support payments using income shares and percentage of income models. Calculate support obligations by state type. Free child support calculator.
What Is Child Support?
Child support is a court-ordered legal obligation for a non-custodial parent to contribute financially to the care and upbringing of their children. It is designed to ensure that children receive financial support from both parents, regardless of whether the parents are married, divorced, or were never in a relationship. Child support covers the basic costs of raising children: food, clothing, shelter, healthcare, education, and related expenses.
In the United States, child support laws are governed at the state level, though federal legislation (the Family Support Act of 1988 and subsequent legislation) requires all states to have numeric guidelines for calculating support. The federal government, through the Office of Child Support Services (OCSS), oversees state child support programs and assists with interstate enforcement.
Child support is distinct from alimony (spousal support), which is paid between former spouses. Child support belongs to the child, not to the receiving parent — it cannot be waived by the custodial parent on behalf of the child. Courts generally require support until the child turns 18 (or 21 in some states), graduates from high school, or becomes emancipated. Some states require support for college expenses as well.
According to the U.S. Census Bureau, approximately 12.9 million parents have custody arrangements involving child support. In 2023, about 62% of custodial parents received some support payments, and the average amount received was approximately $5,620 per year per family.
How Child Support Is Calculated: The Two Main Models
While every state has its own specific guidelines, child support calculations in the US generally follow one of two primary models:
1. Income Shares Model (Most Common — Used by ~40 States)
The Income Shares Model is based on the principle that children should receive the same proportion of parental income they would have received if the parents had remained together. It uses both parents' incomes to determine the total "child-rearing obligation," then allocates that obligation between parents proportionally to their income contributions.
Steps in the Income Shares Model:
- Determine each parent's gross monthly income
- Add incomes together to get combined gross income
- Look up the basic child support obligation from a state schedule based on combined income and number of children
- Calculate each parent's percentage share of combined income
- Multiply the basic obligation by the non-custodial parent's income share
- Add applicable adjustments: health insurance premiums, childcare costs, extraordinary medical expenses
- Adjust for parenting time if shared custody
Example: Paying parent earns $5,000/mo; receiving parent earns $3,000/mo. Combined: $8,000. State schedule obligation for 2 children at $8,000 combined income: ~$1,600. Paying parent's share: 62.5% ($5,000/$8,000). Base obligation: $1,000/month.
2. Percentage of Income Model (Texas, Wisconsin, and Others)
This model applies a fixed percentage directly to the non-custodial parent's income, regardless of the custodial parent's earnings. It is simpler but less responsive to economic disparities between parents.
| Number of Children | Texas Net Income % | Wisconsin Gross % |
|---|---|---|
| 1 | 20% | 17% |
| 2 | 25% | 25% |
| 3 | 30% | 29% |
| 4 | 35% | 31% |
| 5+ | 40% | 34% |
Factors That Affect Child Support Calculations
Beyond the basic income formula, numerous factors can modify the final support amount:
- Parenting time / custody arrangement: Most states reduce support obligations when the non-custodial parent has significant overnight visits (typically 30–40%+ of nights). Equal shared custody (50/50) typically results in the largest reductions, sometimes cutting support by 50% or applying a formula that nearly cancels it out if incomes are similar.
- Healthcare costs: Health insurance premiums paid for the children are typically added to the basic obligation and allocated proportionally. Unreimbursed medical costs above a threshold are often shared in proportion to incomes.
- Childcare costs: Work-related childcare expenses (daycare, after-school care) are usually added to the basic obligation and allocated between parents by income share.
- Other children: Courts may consider whether a parent has legal support obligations for children from another relationship, though policies vary by state.
- Extraordinary expenses: Private school tuition, special needs costs, extraordinary educational expenses, or extracurricular activities may be added at the court's discretion.
- Imputed income: If a court finds that a parent is voluntarily underemployed or unemployed, it may "impute" income based on that parent's earning capacity rather than actual earnings.
- High income situations: Most state guidelines have caps; above those caps, courts use discretion. Low-income situations may have a minimum order regardless of the formula result.
Child Support by State: Key Differences
While federal law requires numeric guidelines, states vary considerably in their approaches:
| State | Model | Key Features |
|---|---|---|
| California | Income Shares (Statewide formula) | Mandatory statewide formula; heavy emphasis on parenting time percentage; low-income adjustment |
| Texas | Percentage of Income | 20%/25%/30%/35%/40% of net income; maximum based on $9,200/month net income |
| New York | Percentage of Income (CSSA) | 17%/25%/29%/31%/35% of combined income up to $163,000; then discretionary |
| Florida | Income Shares | Uses schedules based on combined income; minimum order for low-income payers |
| Illinois | Income Shares | Net income basis; 20%/28%/32%/40%/45% for sole custody; credit for parenting time over 146 overnights/year |
| Wisconsin | Percentage of Income | 17%/25%/29%/31%/34% of gross income; known for simplicity |
| Pennsylvania | Income Shares | Support schedule with adjustments for medical and childcare costs |
Interstate cases (parents living in different states) are governed by the Uniform Interstate Family Support Act (UIFSA), which generally applies the law of the state where the order was originally issued.
Modifying Child Support Orders
Child support orders are not permanent — they can be modified when there is a "substantial change in circumstances." Common reasons for modification include:
- Significant change in either parent's income (usually >15–20% change)
- Change in the child's needs (new medical condition, educational expenses)
- Change in custody arrangement or parenting time
- Child becomes emancipated, reaches age of majority, or completes high school
- Loss of a job (temporary reduction may be granted)
- New child from another relationship (varies by state)
To modify an order, one parent must file a motion with the court that issued the original order. Simply agreeing with the other parent is not legally sufficient — an informal agreement is not enforceable, and the original order remains in effect. Always formalize changes through the court.
Many states have periodic review processes (typically every 3 years) through the child support enforcement agency, where either parent can request a review without having to prove changed circumstances.
Child Support Enforcement
Child support enforcement is handled at the state level through child support enforcement (CSE) agencies, with federal oversight and funding from the Office of Child Support Services. Enforcement tools include:
- Wage garnishment (income withholding): The most common and effective tool — support is deducted directly from the payer's paycheck before they receive it
- Tax refund interception: Federal and state tax refunds can be seized to cover arrears
- License suspension: Driver's license, professional licenses, and recreational licenses may be suspended for non-payment
- Credit reporting: Delinquent support is reported to credit bureaus, damaging the payer's credit score
- Passport denial: Arrears over $2,500 can result in passport denial or revocation
- Contempt of court: In extreme cases, repeated willful non-payment can result in jail time
- Asset seizure: Bank accounts, property, and other assets may be seized for significant arrears
Related Calculators
- Alimony Calculator — Estimate spousal support payments
- Salary Calculator — Net income after taxes
- Budget Calculator — Monthly household budget planner
- Inflation Calculator — Adjust amounts for cost of living changes
- Percentage Calculator — Calculate percentages quickly
Why Use Our Child Support Calculator?
Our calculator offers both the Income Shares Model (used by most states) and the Percentage of Income Model (used in Texas, Wisconsin, and others), so you can choose the approach closest to your state's guidelines. It accounts for both parents' incomes, number of children, and custody arrangement to give you a meaningful ballpark figure before you speak with an attorney or family mediator. All calculations run instantly in your browser — no account, no data storage, completely private.
Important: Child support calculations are highly state-specific and case-specific. This tool provides an educational estimate only. For accurate amounts in your situation, use your state's official child support calculator (most states provide one online through the child support agency) or consult a family law attorney.
Frequently Asked Questions
How is child support calculated?
Most states use either the Income Shares Model (considers both parents' incomes and allocates proportionally) or the Percentage of Income Model (applies a fixed percentage to the paying parent's income). Both models also factor in the number of children, custody arrangement, healthcare costs, and childcare expenses. The exact formula and schedule is set by your state's guidelines.
Does child support change with shared custody?
Yes. Most states reduce child support when the non-custodial parent has significant overnight visits. For equal shared custody (50/50), many states apply a "cross-credit" calculation that only requires the higher-earning parent to pay the difference in their respective obligations. With similar incomes and 50/50 custody, support may be minimal or zero.
What counts as income for child support?
Income for child support purposes typically includes: wages and salaries, self-employment income, bonuses and commissions, rental income, investment income, pension and retirement income, alimony received, and workers' compensation. Public assistance (SNAP, Medicaid) is generally excluded. Courts may also impute income if a parent is voluntarily unemployed or underemployed.
When does child support end?
In most states, child support ends when the child turns 18 or graduates from high school (whichever is later), up to age 19 or 21 depending on the state. Some states require support for college. Support also ends if the child is legally emancipated (marries, joins the military, or a court grants emancipation). Courts can extend support for children with disabilities beyond the normal age limit.
Can parents agree to waive child support?
Courts will not approve a zero-support agreement simply because both parents agree, since child support belongs to the child, not the parents. However, courts can approve agreements where support is waived in exchange for other arrangements (like full custody), provided the arrangement is in the child's best interests. Any agreement must be approved by a court to be enforceable.
What happens if the paying parent loses their job?
The support obligation remains in effect even if the paying parent becomes unemployed. You must file a formal motion to modify the order — an informal agreement to pay less is not legally binding. Courts may grant a temporary reduction during unemployment. Once employed again, you may owe back support (arrears) for any amounts not paid during the unemployment period. Do not stop paying without a court order modification.
Is child support taxable income?
No. Child support is neither deductible for the paying parent nor taxable income for the receiving parent. This is different from alimony (for divorces before 2019), which was deductible/taxable. The IRS treats child support as a transfer of funds between parents for a child's benefit, not as income.
Can child support be paid directly without going through the court?
Some states allow private arrangements between parents for direct payment, but this can be risky. Without going through the state disbursement unit, there is no official record of payments made, and disputes become harder to resolve. If a payment is disputed, cash payments without receipts may be very difficult to prove. Using official payment channels protects both parents.
How does self-employment income affect child support?
Self-employed parents must report gross self-employment income minus legitimate business expenses. Courts scrutinize claimed deductions carefully — expenses that reduce taxable income (like depreciation, home office deductions) may or may not be subtracted for child support purposes. Courts often add back non-cash deductions like depreciation. Hiding income is illegal and courts have tools to uncover unreported income.
How do I find my state's official child support calculator?
Most states provide free online child support calculators through their child support enforcement agency or family court website. Search for "[your state] child support calculator" to find the official tool. Examples: California's DCSS calculator at childsupport.ca.gov, Texas's calculator at OAG.texas.gov, New York's calculator at childsupport.ny.gov. Using your state's official calculator will give you the most accurate estimate.