Child Support Calculator

What is a child support estimate?

Child support is a recurring payment from one parent to the other for a child’s living expenses after separation. This estimate uses a simplified income-shares model on both gross incomes and parenting time — planning guidance, not a court figure.

This is a planning estimate — not legal advice and not a number any court will use. Real orders follow state-specific child support formulas that account for taxes, health insurance, childcare costs, low-income adjustments, and parenting-time rules, and they can land 30% above or below this figure. Verify against your state’s official calculator, usually published by its child support enforcement agency, before relying on any result.

How this calculator works

• Adds both parents’ gross monthly income. If you’re paid weekly or hourly, convert to gross monthly income from any pay period first.
• Applies a simplified obligation schedule: about 20% of combined income for one child, rising to 50% for six or more, with a lower marginal rate above $10,000 per month.
• Presumes the higher earner pays; their share of the obligation equals their share of combined income.
• Applies a parenting-time credit once the higher earner hosts roughly 73 or more nights per year — about 20% of overnights.

How to use the result

1. Treat the figure as a midpoint, not a quote — actual state awards commonly land 30% higher or lower.
2. Check your state’s official child support calculator — most state child support enforcement agencies publish one — before relying on either number.
3. Sanity-check affordability: express the payment as a percentage of take-home pay, and flag anything that squeezes rent, food, or childcare.
4. Gather what real formulas actually count: recent pay stubs, last year’s tax return, health insurance premiums, and childcare receipts.
5. Bring the estimate to a lawyer or mediator as a conversation opener — not as evidence of what is owed.

How accurate is a child support calculator?

Only as accurate as the formula behind it. This one approximates the income-shares method most states use but simplifies the schedule and skips state-specific tax adjustments, healthcare and childcare add-ons, and low-income protections — which is why real awards can differ by 30% or more. A state-specific income shares calculator or an attorney’s worksheet gets closest to a court number; treat any generic child support calculator as budgeting and negotiation prep, not a prediction.

Common mistakes

• Entering take-home pay. Most state child support formulas start from gross income; using net understates the obligation.
• Expecting parenting time to scale linearly. Below about 73 nights a year with the higher earner, this model applies no credit at all — and state thresholds differ.
• Assuming add-ons are included. Childcare, health insurance premiums, and medical costs are typically layered on top of the basic obligation, not inside it.
• Treating the estimate as complete. Alimony, split custody across children, children from other relationships, public benefits, and extraordinary-expense deviations all shift real awards — none are modeled here, and no generic custody calculator captures them.

Once you have a ballpark, the most useful habit is documentation: keep an itemized expense record of shared costs — medical copays, childcare, school fees — because those receipts are exactly what state formulas adjust for.