Yes. If the mother has sole custody, the father is almost always required to pay child support. Both parents share a legal duty to support the child financially, and because the father does not live with the child day-to-day, he meets his share through court-ordered payments to the mother. The amount is set by a formula built into the state’s child support guidelines, using both parents’ incomes and the child’s needs.
Why the Duty Applies Even Without Custody
Every state’s family law code starts from the same premise: a child is entitled to support from both parents, whether or not those parents live together. Sole custody with the mother does not shift the financial obligation onto her alone. It shifts the form of the father’s contribution. Her spending flows naturally through housing, food, and daily care in her home; his flows through a monthly payment.
This is why disagreements with the custody order, limited visitation, or even no visitation at all do not cancel the duty to pay. The obligation is not tied to time with the child. The only way to lower or end it is through the court.
Paternity Has to Be Established First
If the parents were married when the child was born, the law presumes the husband is the father, and a court can order support without an extra step. For unmarried parents, paternity must be legally established before any support order can be issued. No legal parent-child relationship, no enforceable obligation.
Two paths are common. The simpler one is a voluntary acknowledgment of paternity, a form both parents sign, often at the hospital right after birth. It is legally binding and establishes the father’s rights and responsibilities without going to court. The second path is court-ordered genetic testing, used when the alleged father disputes paternity. If he refuses to appear for testing, most courts can enter a default finding of paternity against him.
Once paternity is on the record, the mother can petition for child support. Until then, the court has no authority to order payments.
How the Amount Is Calculated
Child support is not a number the judge picks. Every state uses a formula in its guidelines, and the court plugs in the parents’ financial data to produce the presumptive amount. Judges can deviate in unusual circumstances, but the formula is the starting point.
Income Shares vs. Percentage of Income
Most states use the income shares model. It estimates what the parents would have spent on the child if they still lived together, then splits that amount in proportion to each parent’s income. If the father earns 65% of the combined parental income, he pays 65% of the calculated obligation. A smaller number of states use the percentage of income model, which applies a flat percentage of the non-custodial parent’s income based on the number of children. A few states use a variation called the Melson formula, which builds in each parent’s basic self-support needs before allocating support.
Whatever the model, the calculation starts with both parents’ gross income: wages, bonuses, commissions, rental income, and other recurring sources. Adjustments follow for taxes, health insurance premiums, existing support obligations for other children, and sometimes union dues or mandatory retirement contributions.
Health Insurance and Medical Costs
Health insurance premiums for the child are usually added on top of the base support obligation and divided between the parents by income share. If the father carries the child on his employer plan, the premiums he pays may be credited against his support amount. Unreimbursed medical costs like copays, dental work, therapy, and prescriptions are typically split by income share as well. When a child has significant ongoing medical needs, either parent can ask the court to adjust the order.
Imputed Income for Quitting or Underworking
Courts are alert to parents who quit their jobs or take lower-paying work to shrink a support obligation. When a judge finds a parent is voluntarily unemployed or underemployed, the court can impute income, calculating support on what that parent could be earning rather than what they actually earn. The judge looks at work history, education, job skills, health, and wages available locally. A father with ten years of engineering experience who suddenly takes a part-time retail job will likely have income imputed at his engineering-level earning capacity.
Getting the Order in Place
The process begins when the custodial parent files a petition or complaint with the family court, outlining the child’s needs and both parents’ financial situations. Filing fees vary from nothing in some courts to several hundred dollars in others. The other parent must be formally served and given a chance to respond.
At the hearing, both parents typically submit financial affidavits, recent tax returns, pay stubs, and documentation of expenses. The judge runs the guidelines against the evidence and issues an order specifying the payment amount, frequency, and how payments are made. In many states, payments flow through a centralized state disbursement unit rather than directly between the parents.
Support can usually be made retroactive to the date the petition was filed, not just the date the judge signs the order. If the case takes six months to reach a hearing, the father may owe back support covering that entire period. The court has discretion over how far back to reach, but the filing date is the typical starting point.
What Happens if the Father Doesn’t Pay
A child support order is not a suggestion. When a parent falls behind, enforcement escalates, and the tools are aggressive.
Wage Garnishment
The most common tool is income withholding. The employer deducts child support directly from the father’s paycheck and sends it to the state disbursement unit. Federal law caps how much can be garnished: up to 50% of disposable earnings if he is supporting another spouse or child, or up to 60% if he is not. If payments are more than 12 weeks overdue, another 5% can be taken.1Office of the Law Revision Counsel. 15 USC 1673 – Restriction on Garnishment Many states now start automatic withholding with every new order, not just when a parent falls behind.
Tax Refunds, Liens, and Credit Reporting
The Federal Offset Program intercepts federal tax refunds to collect past-due support, and state tax refunds can be intercepted too. Enforcement agencies can also place liens on real estate and other property, seize funds from bank accounts through financial institution data matching, and report delinquencies to credit bureaus.2Administration for Children and Families. Overview of Federal Parent Locator Service
Passport and License Consequences
A parent who owes more than $2,500 in arrears can be denied a U.S. passport or have an existing passport revoked.3Office of the Law Revision Counsel. 42 USC 652 – Duties of Secretary States also routinely suspend driver’s licenses, professional licenses, and recreational licenses of parents who are significantly behind.
Contempt and Federal Charges
A judge can hold a non-compliant parent in contempt, which carries fines and, in serious cases, jail time. Contempt proceedings are the most common path to incarceration for unpaid support.
Federal criminal law reaches the worst cases. Under 18 U.S.C. § 228, willfully failing to pay support for a child in another state is a federal crime when the debt has gone unpaid for more than one year or exceeds $5,000. A first offense is a misdemeanor punishable by up to six months in prison. If the arrearage exceeds $10,000 or has gone unpaid for more than two years, it becomes a felony carrying up to two years.4Office of the Law Revision Counsel. 18 USC 228 – Failure to Pay Legal Child Support Obligations Federal prosecution is reserved for the most egregious cases, and state or local enforcement must be pursued first.5U.S. Department of Justice. Citizens Guide to US Federal Law on Child Support Enforcement
Changing the Amount Later
A support order is not permanent. Either parent can ask the court to modify the amount when circumstances change significantly. Common grounds include a substantial increase or decrease in either parent’s income, a job loss, a serious illness, a change in the child’s medical needs, or a shift in the custody arrangement. Some states set a specific threshold, such as a 20% change in the calculated obligation.
The parent seeking the change files a motion and provides supporting documentation like updated pay stubs, tax returns, or medical records. The other parent gets to respond. Until the court approves a modification, the original order stays in full effect. Losing a job does not automatically reduce the obligation. A father who simply stops paying or pays less will accumulate arrears he still owes, plus enforcement consequences on top.
When Child Support Ends
Child support is not a lifetime obligation, but it does not always end the day the child turns 18. In most states, support continues until the child turns 18 or graduates from high school, whichever comes later. Some states extend the obligation to 19 or 21. A number of states allow courts to order support through college, particularly if the parents’ original agreement contemplated higher education expenses.
Support may end early if the child becomes legally emancipated through marriage, military enlistment, or a court finding of self-support. It can also continue past the typical age if the child has a physical or mental disability that prevents self-support.
The order itself usually specifies the termination date or triggering event. If it does not, the father should not simply stop paying when the child turns 18. Filing a motion to terminate creates a court record that the obligation has ended. Stopping without that documentation can leave arrears accumulating after the father believes he is done.
Taxes and Who Claims the Child
Child support payments are not tax-deductible for the father and not taxable income for the mother. The money changes hands with no tax effect on either side. What does matter is who claims the child as a dependent, because that controls the Child Tax Credit and other benefits.
Under IRS rules, the custodial parent, defined as the parent the child lived with for the greater number of nights during the year, claims the child by default.6Internal Revenue Service. IRS Publication 504 – Divorced or Separated Individuals When the mother has sole custody, that is almost always her. She can, however, sign IRS Form 8332 to release the claim for a given year, letting the father claim the child instead.7Internal Revenue Service. About Form 8332, Release/Revocation of Release of Claim to Exemption for Child by Custodial Parent Some divorce agreements require the custodial parent to sign this release each year or in alternating years. She can revoke a prior release by filing a new Form 8332 with her return. Only one parent can claim a given child in any tax year, so this is worth negotiating during the support process rather than leaving to default.
When the Parents Live in Different States
Moving does not end the obligation. Under 28 U.S.C. § 1738B, every state must enforce a child support order made by another state’s court, and no state may modify another state’s order unless specific jurisdictional requirements are met.8GovInfo. 28 USC 1738B – Full Faith and Credit for Child Support Orders The Uniform Interstate Family Support Act, adopted in all 50 states, lets a mother in one state register the father’s support order in his new state and use that state’s enforcement tools against him without relitigating the underlying obligation. State child support agencies cooperate to locate non-custodial parents, establish paternity, and enforce orders regardless of where either parent lives.9Office of Child Support Enforcement. Office of Child Support Enforcement