Child Support Calculator: Estimate Payments by State
Free child support calculator that shows how child support is calculated in your state, whether it uses the income shares model, the percentage of income model, or the Melson formula, with adjustments for shared custody, health insurance, and childcare.
Estimate Your Monthly Child Support
Enter your details for a good-faith estimate. This is an educational estimate, not a court order or legal advice. Your actual order depends on your state's official guideline worksheet and full financial disclosure.
Income before taxes. Used for income-shares and Melson states.
Take-home pay. Used by percentage-of-net states like Texas and Alaska.
Enter 0 if the other parent has no income. Enter their imputed (earning-capacity) income if a court has found them voluntarily unemployed.
Nights the children spend with you (0 to 365). At 92+ nights a shared-custody offset may apply.
Other court-ordered child or spousal support, deducted from your income first.
Monthly medical and dental premium for the children.
Monthly daycare or after-school care needed so a parent can work.
How Is Child Support Calculated?
Child support is calculated using a formula set by each state, not by a judge's free-hand judgment. Every state publishes numeric guidelines that turn a small set of facts, the parents' incomes, the number of children, the parenting schedule, and certain add-on costs, into a presumptive monthly amount. The court starts from that guideline figure and can only deviate from it for specific, documented reasons. Because the guideline is a formula, two families with the same numbers should reach the same result, which is exactly what a child support calculator is designed to reproduce.
The first input is income. Depending on the state, the formula uses gross income, net (after-tax) income, or an adjusted figure that subtracts items such as taxes, mandatory retirement, and support already paid for other children. The second input is the number of children covered by the order, because the cost of raising children rises with each child but at a declining marginal rate. The third input is parenting time, measured in overnights per year, which can reduce the paying parent's obligation once it crosses the state's shared custody threshold. Finally, the formula adds mandatory costs like the children's health insurance premium and work-related childcare, splitting them between the parents in proportion to income.
The parent with less parenting time, called the obligor, generally pays support to the parent with more time, called the obligee, on the theory that the obligee already spends their share directly on the children day to day. If you want the estimate turned into an enforceable arrangement, you will ultimately need a written child support agreement or a court order that spells out the amount, the payment method, and how add-on expenses are shared. You can also have an attorney draft that agreement so it matches your state's worksheet.
Key Concept: The Income Shares Model Governs Most States
More than 40 states and the District of Columbia use the income shares model. It rests on a simple principle: a child should receive the same proportion of parental income they would have received if the parents lived together. The state first estimates the combined amount both parents would spend on the children, then divides that amount between them by income share. A parent who earns 60 percent of the combined income is responsible for 60 percent of the support. Because both incomes matter, raising or lowering either parent's income changes the result, which is not true under the flat percentage of income model used by a handful of states.
The Three Child Support Models: Income Shares, Percentage of Income, and Melson
Every state uses one of three guideline models, and knowing which one your state uses is the single most important factor in estimating support. The income shares model is the most common. It combines both parents' incomes, looks up the total basic obligation for that combined income and number of children on a published schedule, adds health insurance and childcare, and then assigns each parent their income-proportional share. States including California, Florida, New York, Illinois, Ohio, Pennsylvania, Georgia, and Michigan follow this approach.
The percentage of income model is simpler and used by a small group of states. It applies a fixed statutory percentage to the paying parent's income based only on the number of children, without regard to the other parent's income. Texas is the best known example, ordering 20, 25, 30, 35, and 40 percent of net resources for one through five children, applied up to a statutory cap on net resources. Wisconsin applies 17, 25, 29, 31, and 34 percent of gross income, Mississippi applies 14, 20, 22, 24, and 26 percent of adjusted gross income, and Alaska applies 20, 27, and 33 percent (plus 3 percent per additional child) of adjusted income. Because only the payer's income counts, these calculations are quick but blunt.
The Melson formula, used only in Delaware, Hawaii, and Montana, is the most detailed. It works in three steps: first it protects a basic self-support reserve for each parent so that neither is pushed into poverty, then it meets the children's primary support needs from the remaining income, and finally it applies a standard-of-living allowance that lets the children share in a higher-earning parent's income. The Melson formula is widely regarded as the fairest of the three, but it is also the most complex to compute by hand. Whichever model applies, a written attorney-drafted child support agreement can memorialize the result and the reasoning behind it.
Pro Tip: Document Every Income Source Before You File
The number that comes out of any child support calculator is only as good as the income you put in. Before you rely on an estimate, gather recent pay stubs, last year's tax return, and records of bonuses, overtime, commissions, and self-employment income. Courts routinely include irregular income that a parent tries to leave out, and they can add back business deductions that are really personal spending. If you believe the other parent is understating income or is voluntarily underemployed, keep evidence of their earning capacity, because that is what supports an imputed income argument later.
Child Support Calculator by State: Which Model Each State Uses
A child support calculator by state has to start with the guideline model that state adopted. The table below shows the model and the income basis for twelve of the most populous states. Income shares states combine both parents' incomes; percentage of income states apply a flat rate to the paying parent's income; Melson states protect a self-support reserve first.
| State | Guideline Model | Income Basis | Notable Rule |
|---|---|---|---|
| California | Income Shares | Both parents, net | Guideline formula, Fam. Code 4055 |
| Texas | Percentage of Income | Obligor, net resources | 20/25/30/35/40% up to a net-resources cap |
| Florida | Income Shares | Both parents, net | Schedule under Fla. Stat. 61.30 |
| New York | Income Shares | Both parents, adjusted gross | CSSA: 17% one child, 25% two |
| Illinois | Income Shares | Both parents, net | Converted to income shares in 2017 |
| Pennsylvania | Income Shares | Both parents, net | Statewide support guideline |
| Ohio | Income Shares | Both parents, gross | Basic schedule updated 2019 |
| Georgia | Income Shares | Both parents, gross | Worksheet with deviations |
| North Carolina | Income Shares | Both parents, gross | Worksheets A, B, and C by custody |
| Michigan | Income Shares | Both parents, net | Michigan Child Support Formula |
| Wisconsin | Percentage of Income | Obligor, gross | 17/25/29/31/34% of gross income |
| Delaware | Melson Formula | Both parents, net | Self-support reserve protected first |
Income basis is generalized; several states adjust gross income before applying the schedule. Always confirm against your state's current official worksheet.
Shared Custody Child Support: How Overnights Change the Number
Shared custody child support recognizes that a parent who keeps the children a substantial number of nights is already paying for food, housing, and daily needs during that time. Most states build a standard amount of parenting time into the base guideline, then apply a separate shared-parenting adjustment once the paying parent's overnights cross a threshold. That threshold varies widely by state, commonly falling somewhere between 90 and 110 overnights per year, though some states set it as high as roughly 40 percent of the year.
Above the threshold, many states use a cross-credit method. The basic obligation is first increased, often by a factor of about 1.5, to reflect the reality that maintaining two homes for the children costs more than one. Each parent's share of that larger obligation is then calculated, and each is credited for the percentage of overnights the children spend with them. The two figures are offset, and the parent who comes out owing more pays the difference. This is why a true 50/50 schedule usually still produces a payment from the higher earner, rather than reducing support to zero.
Because overnights carry real financial weight, parenting-time disputes and child support disputes are deeply connected. If you are negotiating a schedule, it helps to see how a change of even ten or twenty overnights shifts the number in our calculator above. When you and the other parent reach an arrangement, put it in writing through a child support agreement that states both the parenting schedule and the resulting support so there is no dispute later about how the number was reached.
Imputed Income: When Courts Use Earning Capacity Instead of Actual Pay
Imputed income is one of the most litigated issues in child support. When a court believes a parent is voluntarily unemployed or underemployed, it can base support on what that parent is capable of earning rather than on the lower amount they actually report. The purpose is straightforward: a parent should not be able to shrink a support obligation by quitting a good job, turning down promotions, or shifting to cash work that hides income. Courts guard against this by imputing income at the parent's realistic earning capacity.
To decide how much to impute, judges weigh the parent's recent work history, education, professional licenses, job skills, health, and the availability of jobs in the local market. A software engineer who suddenly claims minimum-wage income will likely have income imputed near their prior salary, while a parent with a genuine disability or one who left the workforce to care for an infant is usually not penalized. Imputation is not automatic; the parent asking for it generally has to show both the ability to earn more and an absence of a good-faith reason for the lower income.
If you suspect the other parent is understating income, enter their earning capacity rather than their reported pay in the calculator above to see how the estimate changes, and keep documentation of their qualifications and job history. These issues are fact-intensive and often decide the outcome, so a licensed family law attorney can help you build and present an imputation argument.
Warning: This Estimate Is Not a Court Order
A calculator estimate and a court order are not the same thing. Only a court applying your state's official guideline worksheet, with full financial disclosure from both parents, can set an enforceable amount, and a judge can deviate from the guideline for documented reasons such as high combined income, a child's special needs, split custody, or extraordinary medical or educational costs. Do not stop paying, change what you pay, or agree to a number based on an estimate alone. Use the figure above to plan, then confirm it through your state's worksheet and a licensed family law attorney.
Modifying Child Support After a Change in Circumstances
Modifying child support is available when there has been a substantial change in circumstances since the last order was entered. A child support order is not frozen forever; it is meant to track the family's real situation. Common grounds for modification include a meaningful change in either parent's income, a job loss or new job, a change in the custody or parenting-time schedule, the birth of another child, a new or ended childcare need, or a change in the children's medical needs. Many states also allow a periodic review after a set number of years even without a specific triggering event.
Most states require the change to be significant before they will reopen the order. A common test asks whether recalculating support under the current guideline would move the amount by at least a set percentage, often 10 to 20 percent, or by a set dollar figure. If your income has dropped and you re-run the numbers above, that new estimate is a useful preview of whether you clear your state's modification threshold. Keep in mind that support does not change by itself. You must file a formal motion to modify, and a reduction generally takes effect only from the date you file, not from the date your circumstances actually changed, so filing promptly matters.
When you are ready to change an order, a properly drafted stipulation or motion is what the court reviews. A child support agreement or modification prepared to your state's standards, showing the changed circumstances and the recalculated amount, gives the judge what they need to approve the new figure. You can also request a custom draft tailored to your situation.
What Counts as Income in a Child Support Calculation
Wages, Salary, and Overtime
Base pay is always counted. Courts also include regular overtime, commissions, tips, and bonuses when they are consistent enough to be reliable, which is why a single strong year can raise the number.
Self-Employment and Business Income
Net earnings from a business count, and courts can add back personal expenses run through the business. Self-employment income draws extra scrutiny in both income shares and percentage of income states.
Benefits and Other Sources
Unemployment, Social Security benefits, disability payments, pensions, rental income, and investment income are typically included. Means-tested public assistance is usually excluded from the calculation.
Imputed and Earning Capacity
If a parent is voluntarily unemployed or underemployed, a court can use imputed income based on earning capacity instead of actual pay, so the guideline reflects what the parent could earn.
Frequently Asked Questions
How is child support calculated?
Child support is calculated using your state's official guideline formula, which falls into one of three models. Most states use the income shares model, which combines both parents' incomes, finds the total support the children would receive if the household were intact, and divides it between the parents in proportion to their incomes. A minority of states use the percentage of income model, which applies a flat statutory percentage to the paying parent's income based on the number of children. Three states (Delaware, Hawaii, and Montana) use the Melson formula, which protects each parent's basic self-support needs first and then allocates support with a standard-of-living adjustment. On top of the base figure, courts add the children's health insurance and work-related childcare, and they may adjust for parenting time, other support obligations, and extraordinary expenses.
What is the difference between the income shares model and the percentage of income model?
The income shares model uses both parents' incomes. It estimates the total amount the children would have received if the parents lived together, then each parent is responsible for the share that matches their portion of the combined income. The paying parent (the one with less parenting time) transfers their share to the other parent. The percentage of income model ignores the receiving parent's income and simply applies a fixed statutory percentage to the paying parent's income. For example, Texas orders 20 percent of net resources for one child and 25 percent for two, while Wisconsin orders 17 percent of gross income for one child and 25 percent for two. Income shares is used by the large majority of states because it more closely tracks what an intact household would spend on the children.
How does a child support calculator by state differ from state to state?
A child support calculator by state differs because each state adopts its own guideline model, income definition, self-support reserve, low-income adjustment, and add-on rules. Two parents with identical incomes can owe very different amounts in different states. A child support calculator for Texas applies a percentage of net resources up to a statutory cap, while a child support calculator for California, Florida, or New York combines both incomes under the income shares approach and uses that state's own schedule. States also differ on how they treat overtime, bonuses, self-employment income, and the point at which shared parenting time reduces the order. Always confirm the number against your own state's current worksheet.
How does shared custody affect child support?
With shared custody child support, the number of overnights each parent has with the children can reduce the paying parent's obligation. Most states set a threshold, commonly somewhere between 90 and 110 overnights per year, at which a shared-parenting adjustment begins. Above that threshold, many states multiply the basic obligation by about 1.5 to account for the duplicated costs of maintaining two homes for the children, then credit each parent for the time the children spend with them. The result is a smaller net transfer. Equal 50/50 time does not automatically eliminate support, because the higher earner usually still pays something to keep the children's standard of living consistent across both homes.
What is imputed income in a child support case?
Imputed income is income a court assigns to a parent who is voluntarily unemployed or underemployed. If a judge finds that a parent quit a job, is deliberately working below their earning capacity, or is hiding income to lower a support order, the court can calculate support based on what that parent could and should be earning rather than what they actually report. Courts look at work history, education, skills, local job availability, and prior earnings. Imputed income prevents a parent from dodging support by choosing not to work. It generally does not apply when a parent is genuinely unable to work due to disability, is caring for a very young child, or is unemployed through no fault of their own.
Can child support be modified after it is ordered?
Modifying child support is possible when there has been a substantial change in circumstances since the last order. Common grounds include a significant change in either parent's income, job loss, a change in the parenting schedule or custody, a new child, a change in the children's medical or childcare needs, or the passage of time under a state's periodic review rules. Many states require the change to move the guideline amount by a set percentage (often 10 to 20 percent) or a set dollar figure before they will modify. You cannot change the amount on your own; you must file a motion to modify with the court, and any change generally applies only from the date you file, not retroactively.
Does child support include health insurance and daycare?
In most states the base guideline figure covers ordinary living costs (food, housing, clothing, and everyday needs), and the children's health insurance premium and work-related childcare are added on top and split between the parents in proportion to income. Some percentage-of-income states, including Texas, order medical and dental support as a separate line item rather than folding it into the base percentage. Unreimbursed medical expenses, extraordinary educational costs, and special needs are usually handled as additional shared expenses. That is why our calculator lets you enter health insurance and childcare separately.
Is this child support calculator legally binding?
No. This child support calculator gives a good-faith educational estimate to help you plan, but it is not a court order, a determination, or legal advice. Only a court applying your state's official guideline worksheet can set an enforceable amount, and judges can deviate from the guideline for documented reasons. Use the estimate as a starting point, then have a licensed family law attorney prepare a proper child support agreement or run your state's official worksheet so the order is accurate and enforceable.
Related Legal Tools
Turn Your Estimate Into a Child Support Agreement
An estimate is a starting point. A licensed attorney can draft a state-specific child support agreement that sets out the amount, the calculation, health insurance, childcare, and how future changes are handled, so it holds up in court.