Child Support Calculator
Estimate child support payments based on both parents incomes, custody, and number of children.
Child Support Calculator
Calculator
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Formula: Support = (Combined Income x Child Cost %) x Non-Custodial Share - Custody Offset
Worked example — Parent 2 pays ~$914/month | $10,968/year | 26.1% of Parent 2 income
Formula
Support = (Combined Income x Child Cost %) x Non-Custodial Share - Custody Offset
Under the Income Shares model, the total child-rearing cost is estimated as a percentage of combined parental income (20% for 1 child up to 43% for 6). This obligation is divided proportionally by income share, with adjustments for custody time, health insurance, and childcare costs.
Worked Examples
Example 1: Income Shares Model with Two Children
Problem:Parent 1 earns $5,000/month, Parent 2 earns $3,500/month. Two children, Parent 1 has 70% custody. Health insurance $300/month, childcare $800/month. Income Shares model.
Solution:Combined income = $8,500 Parent 1 share = 58.8%, Parent 2 share = 41.2% Child cost % for 2 children = 28% Basic obligation = $8,500 x 28% = $2,380 Total obligation = $2,380 + $300 + $800 = $3,480 Parent 2 share = $3,480 x 41.2% = $1,434 Custody offset reduces Parent 2 payment Estimated payment: ~$914/month
Result:Parent 2 pays ~$914/month | $10,968/year | 26.1% of Parent 2 income
Example 2: Percentage of Income with One Child
Problem:Parent 1 earns $6,000/month, Parent 2 earns $4,000/month. One child, Parent 1 has 80% custody. Health insurance $200, childcare $500. Percentage model.
Solution:Non-custodial parent (Parent 2) income = $4,000 Percentage for 1 child = 20% Payment = $4,000 x 20% = $800/month Note: In pure percentage model, only payer income matters Health insurance and childcare may be added separately by court Estimated base payment: $800/month
Result:Parent 2 pays $800/month | $9,600/year | 20.0% of Parent 2 income
Frequently Asked Questions
How is child support calculated in the United States?
Child support calculation varies by state, but most states use one of three models. The Income Shares model, used by approximately 40 states, calculates the total cost of raising children based on combined parental income, then divides that obligation proportionally between parents based on each parent's share of the total income. The Percentage of Income model, used by states like Texas and Wisconsin, applies a flat percentage of the non-custodial parent's income. The Melson Formula, used in Delaware, Hawaii, and Montana, is similar to income shares but first subtracts a self-support reserve to ensure each parent can meet their own basic needs. All models consider the number of children, custody arrangement, and additional costs like health insurance and childcare.
What factors affect the amount of child support payments?
Multiple factors influence child support calculations beyond just income. The number of children is a primary factor, with obligations increasing but not linearly for each additional child. Custody arrangement significantly affects payments, as parents with more physical custody time are assumed to spend more directly on the children. Health insurance premiums paid for the children are added to the basic obligation and shared proportionally. Childcare costs for work or education-related care are similarly included. Some states also consider extraordinary medical expenses, educational costs, travel expenses for visitation, and prior child support obligations from other relationships. The age of the children may also matter, as older children typically cost more. Special needs requiring additional resources can increase the obligation.
How does shared or joint custody affect child support amounts?
Shared custody arrangements, where both parents have significant parenting time, typically reduce child support payments compared to sole custody arrangements. Most states apply a custody offset when the non-custodial parent has the children for more than a threshold amount, commonly 25 to 35 percent of overnights. The rationale is that the non-custodial parent incurs direct expenses during their parenting time, such as food, transportation, and activities. Some states use a multiplied offset formula where the basic obligation is multiplied by 1.5 for shared custody to account for duplicate household expenses, then each parent's share is calculated based on income and time. Equal 50-50 custody does not necessarily mean zero child support if there is a significant income disparity between parents.
Can child support be modified after it is ordered?
Yes, child support orders can be modified when there is a substantial change in circumstances. Common grounds for modification include significant changes in either parent's income such as job loss, promotion, or disability. Changes in custody arrangements, the child's needs, or health insurance costs can also justify modification. Most states allow either parent to request a review every three years even without a change in circumstances. To modify support, you typically file a motion with the family court that issued the original order. Some states require showing at least a 10 to 15 percent change from the current order before they will consider modification. It is important to file for modification promptly, as courts rarely make changes retroactive to before the filing date.
What happens if someone does not pay court-ordered child support?
Failure to pay child support can result in serious legal and financial consequences. State child support enforcement agencies have powerful tools at their disposal. Wage garnishment automatically deducts payments from the payer's paycheck before they receive it. Tax refund interception can redirect federal and state tax refunds to cover arrears. Suspension of driver's licenses, professional licenses, and passports are common enforcement actions. Bank account levies can seize funds directly. Credit reporting agencies are notified of delinquent support, damaging the payer's credit score. In severe cases, contempt of court proceedings can lead to fines or jail time. Interest accrues on unpaid support in most states. Some jurisdictions also use property liens and lottery intercepts. Child support obligations generally cannot be discharged in bankruptcy.
What income counts when calculating a child support obligation?
Guidelines typically start from a broad definition of gross income: wages, salary, overtime, commissions, bonuses, self-employment income net of legitimate business expenses, rental and investment income, pensions, and many benefit payments. Some states then convert to net income by deducting taxes, mandatory retirement contributions, and union dues. Means-tested public assistance is usually excluded. Because irregular income such as bonuses is often averaged over several years, the figure you enter should reflect a realistic long-run number.
What is a self-support reserve and how does the Melson formula use it?
A self-support reserve is a floor of income set aside so a paying parent can meet their own basic living costs before support is assessed. The Melson formula applies it explicitly: each parent's primary needs are subtracted first, the children's primary support needs are then met from what remains, and only surplus income is shared as a standard of living allowance. Income shares states often achieve something similar through a low-income adjustment or a minimum order.
How are health insurance premiums and childcare costs treated in the calculation?
These are handled as add-ons rather than being folded into the basic table amount. The portion of the health insurance premium attributable to the children, plus work-related or education-related childcare, is added to the basic obligation and then divided between the parents in the same proportion as their incomes. The parent who actually pays the expense receives credit for it, which is why the paying parent's net transfer can fall even when the total obligation rises.
Why does the obligation not double when a second child is added?
Child-rearing costs show economies of scale. Housing, utilities, transportation, and many household goods are shared across siblings, so the marginal cost of a second child is well below the cost of the first. Guideline tables reflect this with a rising but flattening percentage of combined income as the number of children increases. That is why moving from one child to two adds a meaningful but sub-proportional amount, and each further child adds less again.
How does the calculator convert the combined obligation into one parent's payment?
The model first estimates what an intact household at that combined income would spend on the children, then prorates it. If one parent contributes sixty percent of combined income, that parent is responsible for sixty percent of the total obligation. The custodial parent is presumed to spend their share directly, so only the other parent's share becomes a transfer payment, adjusted for parenting time and any add-on expenses each parent already pays.
References
Reviewed for accuracy by Daniel Agrici, Founder & Lead Developer · Editorial policy
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