CalcKitChild Support Calculator
Parents' incomes & custody
Use monthly net income (after taxes and mandatory deductions). Add-on costs are shared in proportion to income. This calculator uses a simplified income-shares model; each state has its own schedule and rules.
Example: $4,000 + $2,000 incomes, 2 children, 52/313 overnights → Parent A pays Parent B $1,000/month.
Behind the numbers
How child support is calculated
This calculator uses the income-shares model that most states follow in some form: both parents' monthly net incomes are combined, a percentage of that combined income is set aside as the children's basic need, and each parent covers a share of that need in proportion to their income. The percentages used here are a simplified schedule — 17% for 1 child, 25% for 2, 29% for 3, 31% for 4, 33% for 5 and 34% for 6 children — chosen to sit in the range used by many state guideline tables. Child care and health insurance costs are added to the basic obligation and shared the same way. The parent with fewer overnights normally pays their share to the other parent. If each parent has at least 73 overnights a year, a shared-parenting adjustment applies: each share is multiplied by 1.5 and cross-multiplied by the other parent's overnight percentage, and the difference is the transfer.
Combined net income $4,000 + $2,000 = $6,000. Basic obligation for 2 children: 25% × $6,000 = $1,500. Parent A share: ($4,000 ÷ $6,000) × $1,500 = 66.7% × $1,500 = $1,000. Parent B share: 33.3% × $1,500 = $500. Parent A has 52 overnights and Parent B has 313, so no shared-parenting adjustment applies, and Parent A pays Parent B $1,000 per month.
Examples
Examples — basic monthly obligation (no add-ons)
| Combined monthly net income | 1 child (17%) | 2 children (25%) | 3 children (29%) |
|---|---|---|---|
| $3,000 | $510 | $750 | $870 |
| $6,000 | $1,020 | $1,500 | $1,740 |
| $9,000 | $1,530 | $2,250 | $2,610 |
| $12,000 | $2,040 | $3,000 | $3,480 |
Tips before you rely on the number
Use net income, not gross pay — taxes and mandatory deductions come off first in most states.
Keep proof of income, child care bills and health insurance premiums; a court will ask for them.
Check your own state's guideline schedule — percentages and add-on rules vary by state, and some states use a flat percentage of the paying parent's income instead.
Overnights matter: substantial time with each parent can lower the transfer, but it rarely removes it when incomes are unequal.
Support orders can be modified when income or custody changes in a major way — ask a family lawyer in your state about the rules.
Good to know
Frequently asked questions
Is this the amount a court will order?
No. This is a general estimate from a simplified income-shares model. Each state has its own guideline schedule, worksheet and deviation rules, and only a court sets the final amount for your case.
Why is support based on both parents' incomes?
Under the income-shares model, the children are meant to receive the same share of combined parental income they would have received if the household were still together, with each parent contributing in proportion to what they earn.
Does more time with the children lower support?
Often, yes. The parent who has the children more pays for more of their day-to-day costs directly, so the transfer is smaller. With at least 73 overnights each, many states apply a shared-parenting formula, as this calculator does.
Are child care and health insurance included?
They are added on top of the basic obligation here and shared in proportion to income. Enter them in the add-on field. In some states they are handled separately in the court order, so check your state's worksheet.