Child Support Calculator
Income Shares Model · 2026
Parent Incomes (Monthly Gross)
$
Custodial parent
$
Non-custodial parent
Children & Custody
True 50/50 = 182 nights. Sole custody = 0-73 nights.
Additional Expenses (Monthly)
$
$
$
$
Enter both parents' incomes and custody details to estimate monthly child support.
Estimated Monthly Support
$0
Parent B pays to Parent A
⚠️ This is an estimate only. Actual amounts are set by a court using your state's specific guidelines. Always consult a family law attorney.
Income CalculationAmount
Parent A gross income—
Parent B gross income—
Combined monthly income—
Basic child support obligation—
Parent B income share
Additional ExpensesMonthly
Health insurance—
Childcare / daycare—
Medical out-of-pocket—
Education / activities—
Parent B share of extras—
Custody AdjustmentFactor
Parent B overnights/year—
Custody adjustment—
Estimated monthly support—
Annual total—
⚖️
Get expert family law guidance for your situation
LegalZoom · Rocket Lawyer · Connect with local family attorneys
Sponsored: we may earn a commission at no cost to you.
How Child Support Is Calculated
Most states use the income shares model: a guideline table sets what the parents would spend on the children together, and each parent owes a share in proportion to their income. A parent with 58% of combined income owes 58% of that amount, reduced when they have substantial parenting time. Enter both incomes, the children and the overnights above for an estimate.
Child support in the United States is calculated using state guidelines, with the vast majority of states (40+) using the Income Shares Model. This model determines the amount parents would have spent on the child if the family remained intact, then divides that obligation between both parents in proportion to their respective incomes. The resulting amount is called the basic child support obligation.
The non-custodial parent (or the parent with fewer overnights in shared custody) typically pays their proportional share to the custodial parent. Courts may deviate from guideline amounts based on special circumstances such as a child's special needs, extraordinary medical expenses, or a parent's significantly reduced earning capacity. This calculator provides estimates based on standard guideline principles: always verify with an attorney in your specific state.
Income Shares vs Percentage of Income
Income Shares (40+ states): combines both parents' incomes to determine a total obligation, then splits proportionally. Percentage of Income (fewer states, incl. Texas): sets support as a fixed percentage of the non-custodial parent's income only (Texas: 20% for 1 child, 25% for 2, 30% for 3, 35% for 4, 40% for 5+). Delaware uses Melson Formula. Always check your state's specific model.
Shared Custody Impact
When a non-custodial parent has significant parenting time (typically 40%+ overnights), many states apply a shared parenting adjustment that reduces the support obligation. The threshold and formula vary by state. True 50/50 custody (182 overnights) often results in a significantly lower payment than sole custody, and in some cases may eliminate support payments if incomes are similar.
What Income Is Included
Most states include in "gross income": wages and salaries, self-employment income, bonuses and commissions, investment income, rental income, Social Security benefits, unemployment compensation, pension/retirement income. Generally excluded: public assistance (SNAP, Medicaid), SSI. Overtime may or may not be included depending on whether it's consistent or sporadic.
Modifying a Support Order
Child support orders can be modified when there is a "substantial change in circumstances": typically a 15-20% change in income, significant change in custody, or major change in a child's needs. Most states allow review every 3 years regardless. Modifications require a court order: informal agreements to pay less are not enforceable and arrears continue to accrue under the original order.
The Three Guideline Models
Federal law requires every state to publish a child support guideline and review it at least every four years. States use one of three models.
| Model | How it works | Used by |
|---|---|---|
| Income shares | Combines both incomes, reads the total obligation from a table, splits it by income share | About 40 states |
| Percentage of income | A set percentage of the paying parent's income only | A handful of states, including Texas and Mississippi |
| Melson formula | Income shares with a self-support reserve for each parent and a standard of living adjustment | Delaware, Hawaii and Montana |
Texas, for example, sets support at 20% of the paying parent's net resources for one child, 25% for two, 30% for three, 35% for four and 40% for five or more.
Worked Example: Income Shares Step by Step
Parent A earns $5,000 a month and has the child most of the time. Parent B earns $7,000 a month and has about 52 overnights a year. One child, $600 a month of work-related childcare paid by Parent A. Figures use this calculator's approximate table.
- Combine incomes: $5,000 + $7,000 = $12,000 a month.
- Find the basic obligation: the table gives about $1,734 a month for one child at that income.
- Split by income: Parent B has 58.3% of combined income, so owes about $1,012.
- Add extras: Parent B's 58.3% share of $600 childcare is $350.
- Result: about $1,362 a month from Parent B to Parent A.
How Overnights Change the Amount
Same parents, no extras, computed with this calculator. From 20% of overnights the shared parenting cross-credit applies: the obligation is raised by half to reflect two households, and each parent's share is set against the other.
| Parent B overnights | Share of time | 1 child | 2 children |
|---|---|---|---|
| 52 | 14% | $1,012 B to A | $1,488 B to A |
| 73 | 20% | $997 B to A | $1,466 B to A |
| 110 | 30% | $733 B to A | $1,079 B to A |
| 146 | 40% | $477 B to A | $701 B to A |
| 182 | 50% | $220 B to A | $324 B to A |
| 219 | 60% | $43 A to B | $64 A to B |
Even at 50/50 time the higher earner usually still pays something. Real thresholds and multipliers differ by state; some start the adjustment at 25% or more of overnights, and some use a gradual scale instead.
Method and sources. Basic obligation = combined monthly gross income × a per-child percentage, scaled down at higher incomes; this approximates the shape of state income shares tables and is not any one state's table. Shared parenting: cross-credit method (obligation × 1.5, each parent's share netted by the other parent's time) from 20% of overnights. Guideline requirements: 45 CFR 302.56 and the federal Office of Child Support Services. Model grouping: National Conference of State Legislatures. Texas percentages: Texas Family Code section 154.125. Tax treatment: IRS Publication 504. Estimate only; your state's worksheet decides the actual amount.
This calculator provides estimates for informational and educational purposes only. Child support is determined by courts applying your specific state's guidelines. This is not legal advice. Consult a licensed family law attorney in your state for guidance on your specific situation.
Frequently Asked Questions
Child support is calculated using state-specific guidelines. The most common is the Income Shares Model (used by 40+ states): both parents' gross incomes are combined, a basic support obligation is determined from state guidelines tables based on that combined income and number of children, and each parent's share is proportional to their income percentage. The non-custodial parent's share is then adjusted for actual custody time. A handful of states, including Texas and Mississippi, use the Percentage of Income Model: a fixed percentage of the non-custodial parent's income only, regardless of the custodial parent's earnings.
Not necessarily. In 50/50 shared custody, child support may still be ordered if there is a significant income disparity between parents. The higher-earning parent typically pays some support to equalize the children's standard of living in both homes. The amount is usually reduced compared to sole-custody scenarios, often by applying a shared parenting adjustment. If both parents earn roughly equal incomes and have truly equal custody, some states may result in a zero support obligation or a very nominal amount. The specific formula varies significantly by state.
Most states define income broadly for child support: wages and salary, self-employment income (after reasonable business expenses), bonuses and overtime (if regular), commissions, investment income and dividends, rental income, Social Security benefits (retirement and disability), workers' compensation, unemployment compensation, pension and retirement distributions, and in some cases imputed income (what a parent could earn if working full-time). Courts can impute income to a voluntarily unemployed or underemployed parent based on their education, work history, and local job market. New spouse's income is generally not included but may be considered in some circumstances.
Yes, through a formal legal process called modification. To modify support, you must show a "substantial change in circumstances" since the last order. Most states require at least a 15-20% change in the support amount to justify modification. Common grounds: significant income change (job loss, promotion), change in custody arrangement, change in child's needs (medical, educational), change in healthcare or childcare costs. Most states also allow automatic review every 3 years without showing changed circumstances. Modifications are only effective from the date the petition is filed, not from when circumstances changed: this is why prompt action is important.
Unpaid child support (arrears) accumulates with interest and is aggressively enforced. Consequences of non-payment: wage garnishment (automatic in many states), seizure of tax refunds (federal and state), bank account levies, suspension of driver's license, suspension of professional licenses, suspension of passport, contempt of court (can lead to jail time), negative credit reporting, liens on property. Child support arrears do not go away: they cannot be discharged in bankruptcy and have no statute of limitations in most states. The Child Support Enforcement program operates through the Office of Child Support Services (OCSS) and works across state lines.
In most states, child support continues until the child turns 18. Exceptions: if the child is still in high school at 18, support may continue until graduation (up to 19 in many states). Some states extend support through college if the parents agree or the court orders it (New York, New Jersey, and others). Support terminates early upon: child's emancipation (marriage, military service, living independently), adoption by another parent, or death. Support does not automatically terminate: you must typically get a court order ending the obligation to stop payments and avoid continued accumulation of arrears.
States differ on whether support is calculated from gross or net income, and what deductions apply. Common deductions from gross income before calculating support in Income Shares states: mandatory payroll deductions (Social Security, Medicare), state and federal income taxes, union dues, mandatory retirement contributions, health insurance premiums for the child, prior child support paid under other orders. Note: voluntary deductions (401k contributions, voluntary retirement) are generally NOT deducted, courts use actual available income, not choices that reduce it. Always check your specific state's statutes for exactly what is included and excluded.
Healthcare and childcare costs are typically treated as additional obligations on top of the basic support amount, added proportionally to each parent's income share. Health insurance: if one parent provides health insurance for the child, the other parent typically reimburses their proportional share. Extraordinary medical expenses (uninsured): generally split proportionally. Childcare/daycare: work-related childcare necessary for either parent to work is typically added to the basic obligation and split proportionally. Education and extracurricular: varies by state and court discretion, but many courts split these proportionally, especially if both parents agree to the activity.
Imputed income is income attributed to a parent who is voluntarily unemployed, underemployed, or earning below their potential earning capacity. Courts impute income to prevent a parent from intentionally reducing their earnings to minimize support obligations. Factors used: education level, work history and experience, job skills, prevailing wages in the local area, available jobs, health and physical condition. Example: a surgeon who quits to work retail after a divorce may have their surgeon salary imputed for support purposes. Courts generally don't impute income for parents who are primary caregivers to young children or have legitimate reasons for reduced earnings (medical disability, caring for a child with special needs).
Yes, parents can agree to an amount different from the guideline calculation, but the court must approve it. Courts will only approve a deviation if both parties voluntarily agree, the child's needs are adequately met, and approval is in the child's best interest. Parents cannot waive child support entirely in most circumstances because support belongs to the child, not the parents. A court can and will reject an agreement that leaves a child inadequately supported. If circumstances change, either parent can later return to court to modify the agreed amount using standard modification procedures. Document all agreements formally through the court: informal agreements are not enforceable.
Neither. Child support is not taxable income for the parent who receives it and is not deductible for the parent who pays it, under federal tax law. This is different from alimony under divorce agreements made before 2019. Only the custodial parent, as a rule, claims the child for the child tax credit, unless they sign Form 8332 to release the claim to the other parent.
It depends on the state and the number of children. In percentage of income states it is fixed in the law: Texas uses 20% of the paying parent's net resources for one child and 25% for two. In income shares states there is no single percentage: the state table sets a total for the parents' combined income, the share of income it represents falls as income rises, and the total is then split between the parents by income share.