Child support arrears and interest calculator

Work out how much child support is unpaid and the interest your state's law adds to it, month by month.

Estimated amount owed

Choose your state and enter the order and missed payments.

How it works

Arrears are child support payments that were due under an order and not paid. The calculator starts from the monthly amount in the order and the first month that wasn't paid. You can count missed months, or enter the total unpaid amount if you already know it. Payments made since then are applied to the oldest missed months first, which is how most agencies apply them.

Interest depends entirely on the state. Some states set a fixed yearly rate in law, some use a rate that changes during the year, some charge interest only when a court orders it after finding that nonpayment was willful, and some don't charge interest at all. When a state's rate isn't fixed, the calculator asks you for the rate in your case.

For states with interest, the calculator charges simple interest: each month, one-twelfth of the yearly rate is applied to the balance that is past due, and the last, partial month is prorated by the number of days. A state's grace period, such as interest starting 30 days after a payment was due, is applied before a missed payment starts to earn interest. Texas charges interest only on the unpaid amount above one month's payment, and the calculator follows that rule.

The result is an estimate. Official balances come from the state child support agency's or the court's records, which reflect the exact dates payments were received, how they were applied, and any interest a court waived or reduced.

Worked example

A parent misses every $500 monthly payment from January to December 2025. By January 1, 2026 the unpaid support is $6,000.00. At 6% a year simple interest, with each missed payment earning interest from the following month, interest adds $165.00, for a total of $6,165.00.

Interest on child support by state

Interest on unpaid child support in the states this site covers
State	Interest	Rule
Alabama	7.5% a year	In Alabama, child support judgments entered on or after September 1, 2011 accrue interest at 7.5% a year. Older judgments carry the rate in force when they were entered: 12% a year for judgments entered from November 13, 1981 through August 31, 2011, and 6% before that. After 12 months of full payments, a parent can ask the court to rebate the interest if each person owed the interest agrees in writing. The law doesn't say whether the interest is simple or compound.
Alaska	6% a year	In Alaska, interest on unpaid child support is 6% a year (or a lower maximum rate set by federal law). The Child Support Enforcement Division charges it monthly on the principal arrears owed at the end of the previous month, less payments received that month, starting on the last day of the month after a payment was due. An obligor whose current support is being withheld from wages, unemployment or disability payments isn't charged interest on late current payments.
Arizona	10% a year	Arizona law charges simple interest of 10% a year on unpaid support, on the principal only, starting at the end of the month after the month the payment was due.
Arkansas	10% a year	In Arkansas, child support that becomes due and remains unpaid accrues interest at 10% a year, unless the person owed the support (or their lawyer) asks before the interest accrues that the judgment not accrue interest (Ark. Code Ann. § 9-14-233). The state child support office says interest can be collected once a court reduces it to a judgment. The law doesn't say whether the interest is simple or compound.
California	10% a year	California charges 10% simple interest a year on unpaid child support, the legal rate on money judgments.
Colorado	10% a year	Colorado law allows interest on child support arrears due on or after July 1, 2021 at two percentage points above the 8% statutory rate (10% a year), compounded annually. The parent owed support may waive it, and a court may disallow it for good cause. Arrears due before July 1, 2021 carry 12%, which may be compounded monthly.
Connecticut	Only if a court orders it	Connecticut's child support statutes and guidelines set no interest rate on arrears. A court may decide to add interest of up to 10% a year under a general statute (C.G.S. § 37-3a) as damages when it finds the support was wrongfully withheld, and it decides the date interest starts.
Delaware	No interest	Delaware doesn't add interest to unpaid child support. Delaware's child support agency (DCSS) reports that no Delaware statute addresses interest on arrears, that it doesn't calculate interest on arrears, and that Delaware doesn't charge interest on retroactive support. Each unpaid installment has the force of a Family Court judgment; past-due support is usually repaid at 20% of current support each month, and at least $20.
District of Columbia	No interest	The District of Columbia doesn't add interest to unpaid child support. The District's child support agency reports that it doesn't use interest to discourage missed payments, that it doesn't calculate interest on arrears or on retroactive support, and that it relies on other civil and criminal enforcement tools instead. Each unpaid payment still becomes a money judgment when it is due.
Florida	Set periodically by the state	Florida charges interest on support judgments at the rate the Chief Financial Officer sets every quarter. Enter the rate in force for the period; the rate from July 1, 2026 was 8.06% a year.
Georgia	7% a year	Georgia law sets interest of 7% a year on child support, starting 30 days after each payment is due (a court can change the start date). The person owed support doesn't need a separate judgment to collect it, and a court can apply, reduce or waive past-due interest after weighing factors such as good cause for nonpayment and hardship. Georgia's Division of Child Support Services says it calculates interest at 7% once a parent is 30 days behind, on arrears due from January 1, 2007. We didn't locate an official source that says whether the interest is simple or compound.
Hawaii	Only if a court orders it	Hawaii's child support statutes and guidelines don't add interest to missed payments; we found no provision that does. A child support arrearage reduced to a court judgment can carry post-judgment interest at Hawaii's judgment rate of 10% a year (HRS § 478-3, whose case notes cite an appeals decision awarding interest on a child support arrearage).
Idaho	Set periodically by the state	Idaho's child support agency reports that Idaho law applies the legal rate of interest to child support arrears. The rate on a court judgment is 5% plus a one-year Treasury base rate that the State Treasurer sets each July 1, fixed when the judgment is entered and calculated on a 365-day year. It is 8.875% for judgments entered from July 1, 2026 to June 30, 2027. The agency says it calculates interest on arrears only when an order provides for it and says the debt will be paid through Idaho Child Support receipting.
Illinois	9% a year	Illinois law sets simple interest of 9% a year on unpaid support, applied monthly to the unpaid balance. The state child support agency only enforces interest a court has ordered.
Indiana	Only if a court orders it	Indiana courts may order interest on late child support only when the person or agency entitled to the support asks. The rate can be at most 1.5% a month (18% a year). The statute doesn't say whether the interest is simple or compound.
Iowa	10% a year	Interest on unpaid child, spousal or medical support payments starts 30 days after a payment is due and accrues at 10% a year (Iowa Code § 535.3(2)). It doesn't accrue on amounts paid through income withholding that are late only because of the employer's pay cycle. The statute doesn't say whether the interest compounds.
Kansas	10% a year	In Kansas each unpaid support payment becomes a judgment when it is due. Kansas law presumes that applying interest at 10% a year gives the correct total of interest on support judgments; a person who disputes that total has to prove a different amount. The statute doesn't say whether the interest is simple or compound.
Kentucky	12% a year	In Kentucky, a judgment for unpaid child support bears 12% interest a year, compounded annually, from the date the judgment is entered (for judgments entered on or after June 29, 2017). Interest runs on the judgment for the arrears; the statute doesn't make interest start automatically on each missed payment.
Louisiana	Only if a court orders it	Louisiana doesn't add interest to past-due child support automatically. The state's child support agency (DCFS Child Support Enforcement) doesn't calculate interest on delinquent payments and reports that no Louisiana statute addresses interest on support arrears. Each past-due payment is a judgment by operation of law, and if a parent gets a court judgment for interest owed, DCFS can enforce it.
Maine	Only if a court orders it	Maine law lets the DHHS commissioner collect interest of 6% a year on support debt owed to the department (19-A M.R.S. § 2354), such as support assigned while a family received public assistance. We didn't locate an official source that adds interest automatically to support owed directly to a parent; the court judgment interest statute (14 M.R.S. § 1602-C) sets the rate for civil judgments generally.
Maryland	Only if a court orders it	We found no Maryland child support statute that adds interest to missed payments; interest on past-due support is up to the court. In a 2025 reported decision (Pellet v. Pellet), the Appellate Court of Maryland upheld a trial court's discretionary award of pre-judgment interest on child support arrears. Once a court enters a money judgment for the arrears, the judgment carries Maryland's legal rate of 10% a year on the amount of the judgment.
Massachusetts	6% a year	In cases the Department of Revenue enforces, interest of 0.5% a month (6% a year) and a separate penalty of 0.5% a month are charged on the total past-due support at the end of each month, once it exceeds $500. Neither is charged on interest or penalties, or for a month in which the current support due was paid.
Michigan	Only if a court orders it	Michigan adds no automatic interest. A court may order a surcharge on arrears only after finding the nonpayment willful; it is assessed twice a year at a rate tied to five-year Treasury notes and doesn't compound.
Minnesota	No interest	Since August 1, 2022, interest no longer accrues on past, current or future child support judgments in Minnesota. Interest that accrued before then can still be owed.
Mississippi	Only if a court orders it	In Mississippi, interest on past-due child support is collected when a court adjudicates it, with the principal and the interest stated separately in the order. The state child support agency (MDHS) asks for 8% simple interest unless the underlying judgment set a different rate.
Missouri	12% a year	Missouri law charges simple interest of 1% a month on delinquent support under orders entered on or after September 1, 1982. Interest accrues at the end of each month on the arrearage, less that month's installment. To collect it, the person owed support files a sworn payment-history affidavit with the circuit clerk.
Montana	Only if a court orders it	Montana's child support agency (CSSD) does not calculate or add interest to unpaid child support. It collects interest only after the unpaid interest has been reduced to a lump-sum judgment by an order. Montana judgments carry simple interest at the bank prime rate on the day of judgment plus 3%, with the prime rate reset each January 1.
Nebraska	Set periodically by the state	In Nebraska, delinquent child support draws simple interest at the judgment interest rate (Neb. Rev. Stat. § 45-103) in effect on the date of the most recent support order or decree. A payment becomes delinquent the day after it is due, and interest doesn't accrue until 30 days after that. The State Court Administrator publishes the rate; from July 16, 2026 it is 5.970% a year. The Title IV-D Division of DHHS computes the interest on payments made through the State Disbursement Unit.
Nevada	Set periodically by the state	When a court sets the amount of child support arrears in Nevada, it includes interest on each unpaid payment from the date it was due, unless paying it would be an undue hardship. The rate is the prime rate at the largest bank in Nevada on January 1 or July 1, as set by the Commissioner of Financial Institutions, plus 2%, and it is adjusted every January 1 and July 1 (8.75% from July 1, 2026: a 6.75% prime rate plus 2%). Interest keeps accruing until the amount is paid. We didn't locate an official source that says whether the interest is simple or compound.
New Hampshire	Set periodically by the state	In New Hampshire each child support payment becomes a judgment when it is due, and the New Hampshire Supreme Court has held that unpaid payments accrue interest at the judgment rate from the date each one falls due. The judgment rate is an annual simple rate the State Treasurer sets for each calendar year (5.7% for 2026). For support owed to the state, DHHS may waive interest if that helps collect the debt.
New Jersey	Set periodically by the state	Unpaid child support is a judgment by operation of law and accrues post-judgment interest like other civil judgments. Probation calculates simple interest when the person owed support asks for it, using the court rule rate in effect for each year the judgment was open. For 2026 the rate is 4.5% for judgments up to the Special Civil Part limit and 6.5% above it; for 2027 it is 4.0% and 6.0%.
New Mexico	4% a year	In New Mexico, interest of 4% accrues on delinquent child support from the date each payment is delinquent until it is paid, and at 4% on a consolidated judgment for delinquent support. Support is due on the first of the month unless the order says otherwise and is delinquent if not paid by then. Payments go first to current support, then to delinquent support, and only then to interest. The statute doesn't say whether the interest is simple or compounded.
New York	Only if a court orders it	New York charges interest on arrears only when a court finds the default willful, at the 9% judgment rate, from each payment's due date.
North Carolina	No interest	North Carolina's child support agency doesn't charge interest on arrears.
North Dakota	Set periodically by the state	In North Dakota, past-due child support ordered by a North Dakota court accrues simple interest at the judgment rate, which the State Court Administrator sets each December as the Wall Street Journal prime rate plus 3 points, rounded up to the next half point. The rate is 10% for 2026 (11% in 2025). Support is past due once it is unpaid in a month before the current month, and interest may not be compounded. Child Support may suspend or waive interest under a payment plan.
Ohio	Only if a court orders it	Ohio charges interest on arrears only if a court finds the default willful; it then uses the statutory judgment rate set each year by the Tax Commissioner. Enter the rate the court ordered.
Oklahoma	2% a year	In Oklahoma, court-ordered past-due child support draws interest at 2% a year. Payments that fall due after the current order is set draw interest from the date they become delinquent; a lump-sum judgment draws interest from the first day of the month after it is entered. Oklahoma Human Services calculates simple interest, starting the month after the arrears exceed one month's current support, and charges no interest on unpaid cash medical support.
Oregon	9% a year	Oregon's legal rate of interest on money judgments is 9% a year, simple interest (ORS 82.010(2)). The support statutes refer to interest accruing under that section on support payments, separately from when a payment counts as delinquent (ORS 25.166(4)). The Child Support Program's website doesn't explain when it charges this interest on a particular case.
Pennsylvania	No interest	Pennsylvania's support law doesn't charge interest on arrears. A court may add a penalty of up to 10% on arrears 30 days or more overdue if it finds the nonpayment was willful.
Rhode Island	12% a year	Rhode Island law assesses interest at 12% a year on any child or spousal support debt that is due and owing, unless the Family Court relieves the responsible parent of it for good cause. The statute doesn't say whether the interest is simple or compound.
South Carolina	Set periodically by the state	In South Carolina, the South Carolina Supreme Court has held that a family court order for periodic child support is a judgment and that each unpaid payment draws post-judgment interest from the date it was due, unless the court's order provides otherwise. For judgments entered on or after July 1, 2005, the rate is the prime rate in the Wall Street Journal's first edition of the year plus 4 points, compounded annually, as confirmed by the Supreme Court each January: 10.75% from January 15, 2026, through January 14, 2027. Interest under the earlier law is simple. Retroactive support back to the date of conception also accrues interest at this rate.
South Dakota	12% a year	In South Dakota, each unpaid support payment becomes a judgment by operation of law once it is due. The Department of Social Services or the parent owed support may collect interest on the unpaid principal balance at the Category D rate, which is 1% a month or fraction of a month (12% a year). Collecting it is optional: the law says the department or the parent "may" collect it.
Tennessee	6% a year	Unpaid child support becomes a judgment. Since July 1, 2018, arrears in cases not handled by the state child support program (non-Title IV-D) accrue interest at 6% a year, and a court may lower that rate or set no interest. In state child support program (Title IV-D) cases, interest accrues only if a court makes a written finding, at no more than 6% a year. The law doesn't say whether the interest is simple or compound.
Texas	6% a year	Texas charges 6% simple interest a year on support that is more than 30 days late (counted on the amount above one monthly payment), until it is paid.
Utah	Set periodically by the state	Utah's Office of Recovery Services says interest may accrue on a child support debt by law under the judgment interest statute, but it does not calculate or collect interest unless the interest has been reduced to a specific amount in a court order or judgment. Judgments bear the federal post-judgment rate as of January 1 plus 2% (5.51% for judgments entered in 2026), and the rate in effect when the judgment is entered stays the same for the life of the judgment. We didn't locate an official source that says whether the interest is simple or compound.
Vermont	6% a year	Vermont charges no interest on unpaid child support. Instead, a surcharge of one-half percent a month (6% a year), not compounded, is assessed monthly on past-due support since January 1, 2012 (12% a year from July 2004 to 2011). Each payment becomes a judgment when it is due, and payments go first to current support, then to arrears, then to the surcharge. A court can discharge surcharge for a period when the paying parent could not comply.
Virginia	6% a year	Virginia charges interest on child support arrears at the 6% a year judgment rate unless the parent owed support waives it in writing; the child support agency doesn't collect it from an obligor who is a minor. The statutes don't say whether the interest is simple or compound.
Washington	12% a year	Washington law sets interest of 12% a year on judgments for unpaid child support under a superior court or administrative order. The Division of Child Support does not charge or collect interest unless it has been reduced to a judgment. The statute doesn't say whether interest is simple or compound or when it starts.
West Virginia	5% a year	In West Virginia, interest under the domestic relations chapter is 5% a year, simple interest only, on the unpaid principal; the Bureau for Child Support Enforcement charges 5% simple interest on past-due support. The parents can agree to a payment plan that clears the arrears within 60 months, and the court can then suspend the interest and later forgive it.
Wisconsin	6% a year	Wisconsin charges simple interest of 0.5% a month (6% a year) on past-due support once the amount past due equals or exceeds one month's support. The statute sets 1% a month and lets the Department of Children and Families use 0.5% instead, which is the rate it charges. No interest is charged on unpaid birth costs or fees.
Wyoming	No interest	In Wyoming, an unpaid child support installment becomes a judgment by operation of law on the date it is due, but it does not bear interest: the 10% judgment interest rate does not apply to child support installments that became judgments on or after July 1, 1990 (W.S. 1-16-102(c)). Instead, an installment not paid within 32 calendar days is subject to a one-time automatic late payment penalty of 10% of the unpaid amount, which the parent owed the support claims by filing a sworn affidavit with the clerk of court (W.S. 1-16-103).

Frequently asked questions

Do all states charge interest on unpaid child support?

No. Some states charge a fixed rate set by law, some use a rate that changes during the year, some charge interest only when a court orders it, and some charge none. The table on this page shows the rule for each state the site covers.

How is interest on child support calculated?

Most states charge simple interest: a yearly rate applied to the unpaid balance, without interest on interest. This calculator applies one-twelfth of the yearly rate to the balance each month, prorates the last month by days, and follows the state’s grace period before interest starts.

Does this tell me exactly what I owe or am owed?

No. It is an estimate. The child support agency’s or court’s payment records decide the official balance, including how payments were applied and whether interest was ordered or waived.

Can arrears be forgiven or reduced?

Past-due support generally can’t be reduced retroactively. Some states let a court waive or reduce interest, and some agencies have arrears programs; ask the state child support agency.