Free Child Support Calculator (+ Guide)

What is a child support calculator?

A child support calculator applies a state's child support guideline to the parents' incomes to estimate the support a court would start from.

This one covers five states, each with its own formula from its own law, and says which numbers it used. Every state adds health care and other costs on top, and judges can depart from the guideline.

How it works

Pick the state first, since each asks for different numbers.

California's formula

California Family Code section 4055 sets the statewide guideline, in its current form since September 1, 2024.

• The formula: CS = K[HN − (H%)(TN)], where HN is the higher earner's net monthly disposable income, TN both parents' together, and H% the higher earner's share of time with the children
• K: 1 plus H% (or 2 minus H% above 50%) times a fraction that falls as income rises, 0.25 for a combined $5,001 to $10,000 a month
• More children: multiply by 1.6 for two, 2 for three, 2.3 for four, up to 2.86 for ten
• Who pays: a positive result is paid by the higher earner, a negative one by the lower earner

When the paying parent's net income is below full-time minimum wage, $16.90 an hour in 2026 according to the California Labor Commissioner, a court may lower support, and the calculator shows how far.

Texas's percentages

Texas Family Code chapter 154 sets support as a share of the paying parent's monthly net resources.

• The percentages: 20% for one child, 25% for two, 30% for three, 35% for four, and 40% for five or more
• Low income: under $1,000 of net resources a month, it's 15%, 20%, 25%, 30% and 35%
• The cap: the guideline applies to net resources up to $11,700 a month from September 1, 2025, as the attorney general's 2026 tax charts state
• Net resources: income less Social Security, Medicare, federal income tax for a single person with the standard deduction, state income tax, union dues and the child's health insurance

The calculator turns gross wages into net resources the way the attorney general's charts do, so $4,000 a month of wages is $3,395.67 of net income.

Florida's income shares schedule

Florida Statutes section 61.30 adds both parents' net incomes and reads the child support need from a schedule.

• The schedule: from $800 to $10,000 of combined net income a month, in $50 steps, for one to six children; above $10,000, the need grows by 5% of the extra income for one child, up to 12.5% for six
• Each parent's share: the need times each parent's share of the combined income
• Substantial time-sharing: when each parent has at least 20% of the overnights, each share is multiplied by 1.5 and by the other parent's share of overnights, and the difference is paid
• Low income: below $800 combined, the court decides case by case

Between two rows of the schedule, the calculator reads proportionally between them, so a worksheet that uses one row can differ by a few dollars.

Mississippi's percentages

Mississippi Code section 43-19-101 sets support as a share of the paying parent's monthly adjusted gross income.

• The percentages: 14% for one child, 20% for two, 22% for three, 24% for four and 26% for five or more
• Adjusted gross income: gross income less federal, state and local taxes, Social Security, mandatory retirement and support ordered for other children
• High and low income: above $100,000 or below $10,000 a year, the court makes a written finding on whether the guideline is reasonable

The calculator takes the adjusted gross income you type, less any support you already pay for other children.

New York's Child Support Standards Act

New York's Child Support Standards Chart, released March 1, 2026, sets the percentages and limits.

• The percentages: 17% of combined parental income for one child, 25% for two, 29% for three, 31% for four, and at least 35% for five or more
• The cap: combined income up to $193,000; above it, courts may use the percentages but don't have to
• The paying parent's share: the total is split by each parent's share of the combined income
• Low income: support can't push the paying parent under the $21,546 self-support reserve, with $600 a year as the floor, and it's $300 a year when it would leave less than the $15,960 poverty line

Income here is after Social Security and Medicare taxes, which the calculator takes off for you.

Worked examples

Each state has its own example, which loads with Try an example.

• California: $6,000 and $2,000 of net income a month, one child, with the higher earner having the children 20% of the time. K = 1.2 × 0.25 = 0.3, and 0.3 × ($6,000 − 20% × $8,000) = $1,320 a month
• Texas: $6,000 of gross wages a month, two children, $250 a month of the child's health insurance. Net resources are $4,956.83 less $250, and 25% of that is $1,176.71 a month
• New York: $75,000 and $45,000 a year, one child. After FICA, 17% of the combined income times the paying parent's share is $11,775 a year, about $981 a month
• Florida: $5,000 and $3,000 of net income a month, one child, and 73 of 365 overnights with the paying parent. The need is $1,290, and the time-sharing method leaves $822 a month
• Mississippi: $4,000 of adjusted gross income a month and two children. 20% of that is $800 a month

Each is a starting point a court would build on, adding health care and child care where they apply.

Mistakes to avoid

These are the slips that come up most.

• Using one state's guideline for another: the formulas and caps differ a lot
• Leaving out the costs courts add on top, such as health insurance and child care
• Treating the estimate as the order, when judges can depart from the guideline

Who is the child support calculator for?

It's for parents in California, Florida, Mississippi, New York or Texas preparing for a conversation with a lawyer or mediator, and these tools help around it.

• Paycheck calculator – for take-home pay
• Hourly to salary calculator – to turn a wage into a yearly income
• Tax rates by country – if a parent lives abroad

For any other state, its child support agency publishes its own guideline and often its own calculator.