Child Support Calculator
Before-tax income from all sources: wages, bonuses, self-employment, investments, rental income
Before-tax income from all sources: wages, bonuses, self-employment, investments, rental income
Percentage of overnights Parent 1 (paying parent) has per year. 40%+ triggers shared parenting formula.
Daycare, after-school programs, summer camps — shared proportionally by income
Children's portion of health insurance premium only — shared proportionally by income
Enter Both Parents' Incomes
Fill in both parents' gross monthly income, the number of children, and parenting time to see an estimated monthly child support obligation.
How to Use the Child Support Calculator
Enter Both Parents' Gross Monthly Income
Input each parent's total gross monthly income before taxes — including wages, bonuses, self-employment earnings, investment returns, and rental income. Be as accurate as possible: the income split directly determines each parent's share of the obligation.
Set the Number of Children and Parenting Time
Select how many children are covered by this support order. Then use the slider to set the paying parent's percentage of parenting time (overnights per year). Reaching 40% — about 146 overnights — triggers the shared parenting formula, which can significantly reduce the net payment.
Add Shared Expenses
Enter monthly child care costs (daycare, after-school programs) and the children's health insurance premium. These are added proportionally to each parent's base obligation. For more complex situations, expand the Advanced Inputs to add prior support orders, alimony, and extraordinary medical expenses.
Review Results and Sensitivity Analysis
The results show your estimated monthly and annual payment, income share split, obligation component breakdown, and a sensitivity chart showing how the payment changes across parenting time percentages. Use Export CSV to save results or Print to create a paper record for your attorney consultation.
Frequently Asked Questions
What is the Income Shares Model?
The Income Shares Model is a child support calculation approach used by approximately 40 U.S. states. It starts with the principle that children should receive the same proportion of parental income they would have had if both parents lived together. The model adds both parents' gross monthly incomes, applies a state guideline percentage based on the number of children, and then allocates the resulting base obligation to each parent proportionally based on their share of combined income. This means both parents contribute according to their financial capacity, rather than the entire burden falling on one parent. Child care costs and health insurance premiums are then split proportionally and added to the base obligation to arrive at the net monthly payment.
What triggers the shared parenting formula?
The shared parenting formula is triggered when the paying parent (non-custodial parent) has 146 or more overnights per year with the child — equivalent to approximately 40% of the year. When this threshold is reached, the base obligation is multiplied by 1.5 before being split. This multiplier recognizes that both parents must maintain separate households equipped for the child, resulting in higher combined household costs. The formula then nets out each parent's obligation based on the other parent's time, which typically results in a lower net payment than the standard formula. The sensitivity chart in this calculator shows the exact breakpoint where this shift occurs.
What counts as gross income for child support?
Gross income for child support purposes is broadly defined and includes: wages and salary, overtime and bonuses, commissions and tips, self-employment income (revenue minus ordinary/necessary business expenses), rental income, investment dividends and capital gains, pension and retirement distributions, Social Security and disability benefits, workers' compensation, unemployment benefits, and income from trusts or inheritances. Courts can also impute income to a parent who is voluntarily unemployed or underemployed, assigning what the parent could be earning based on their education, work history, and the local job market. Gifts and in-kind income from a new partner's household may also be considered in some jurisdictions.
How does prior child support for other children affect the calculation?
Under the Income Shares Model, child support orders you are currently paying for children from a prior relationship are deducted from your gross income before calculating your income share for the current order. This adjusted income — sometimes called 'net income' or 'adjusted gross income' — is the figure used to determine your proportional share of the combined obligation. The logic is that income already legally committed to other children should not be double-counted for a new support order. Spousal maintenance (alimony) you are currently paying is similarly deductible. However, voluntary payments or informal support arrangements that are not court-ordered may not qualify for this deduction.
Can child support be modified after it is set?
Yes. Child support orders are modifiable when there is a substantial change in circumstances. Under most state guidelines, you can request a modification every three years without needing to show a change — the court will review the order at that point. Outside of the three-year window, you generally need to demonstrate a significant change, such as a 15% or greater change in either parent's income, a job loss, a major change in parenting time, a significant change in the child's needs (such as a new medical diagnosis), or one parent gaining or losing a child from another relationship. Modifications are not automatic — you must file a petition with the court. The order remains in effect as-is until a new order is entered.
How is child support typically enforced?
Once a child support order is entered by the court, enforcement mechanisms are strong. The most common tool is an income withholding order (wage garnishment), which automatically deducts support payments from the paying parent's paycheck and remits them to the state disbursement unit. Other enforcement tools include interception of state and federal tax refunds, suspension of driver's licenses and professional licenses, denial of passport applications, reporting to credit bureaus, contempt of court proceedings (which can result in fines or jail time), and placing liens on property. Failure to pay child support can become a federal crime if amounts are large enough and the parent crosses state lines to avoid payment.