Child Custody Cost Calculator

Separating parents face two money questions at once, and they are usually confused with each other. The first is the ongoing one: how much child support will change hands every month, for years. The second is a one-off: what the legal process itself costs to get through. This page estimates both, and the monthly support figure is the headline because over any realistic timescale it is much the larger number.

The support estimate

The calculator uses the percentage-of-income model, the simpler of the two approaches American states use:

Monthly support = (Non-custodial parent’s net income × percentage) ÷ 12

The percentage starts at 20% for one child and adds 5 for each additional child, capping at 50%:

Read that number as a rough order of magnitude, not as what a court will order. Roughly two thirds of states do not use this model at all. They use income shares, which combines both parents’ incomes, works out what an intact household at that income would spend on the children, and divides it in proportion to earnings. A parent with a high-earning ex can owe substantially less under income shares than the table above suggests. Melson-formula states differ again. Overnight counts, existing support orders, health insurance premiums and childcare all adjust the final figure, and every state publishes its own worksheet.

What the legal process costs

The ranges below are approximate United States figures and move with region and year. They are shown for context; the calculator does not use them to compute your support.

Contested cases run about four and a half times a mediated one at the midpoint, and the gap widens fast once expert witnesses appear. A custody evaluator or child psychologist writing a report and testifying adds $3,000 to $10,000 on its own, and a guardian ad litem, the attorney appointed to represent the children rather than either parent, adds $1,500 to $5,000 more. Neither is included in the ranges above. If your attorney has given you a number, put it in the optional field and the calculator will fold it into a first-year total instead.

Childcare

Childcare is entered as an annual figure and split evenly, which is the common default when parents share custody roughly equally. Courts frequently order it split in proportion to income instead, so if the two of you earn very different amounts, expect the real split to move.

Worked example

Net income $60,000, two children, a contested case, and $12,000 a year of childcare.

• Support: $60,000 × 25% = $15,000 a year, or $1,250 a month
• Legal fees: contested, so $10,000 to $50,000, midpoint $25,000
• Childcare share: $12,000 ÷ 2 = $6,000 a year

The support alone comes to $225,000 over fifteen years. That is the number worth negotiating carefully, and it is the reason spending on mediation to avoid a fight over percentage points is usually money well spent.

None of this is legal advice, and no calculator can substitute for your state’s worksheet or an attorney who has read your file.