Reviewed for current 2026 law
New Mexico Child Support Arrears Calculator: 4% Interest
New Mexico charges 4% simple annual interest on delinquent child support under Section 40-4-7.3. Project a principal balance at that child-support-specific rate, then test a monthly payment against a separately reconciled principal-and-interest ledger. The official ledger still controls the dated case balance and payoff.
Reviewed by SupportDecode Editorial Team Page content reviewed Sources Methodology Update log
arrears calculator
Estimated arrears with interest: $5,200.00
Interest of $200.00 at 4% simple per year (NMSA 1978, § 40-4-7.3).
| Line item | Amount |
|---|---|
| Arrears principalNMSA 1978, § 40-4-7.3 — interest on delinquent support (New Mexico Legislature) | $5,000.00 |
| Simple interest at 4% per year for 12 month(s) (NMSA 1978, § 40-4-7.3)Delinquent child support and consolidated child-support judgments accrue 4% annual simple interest under § 40-4-7.3. The separate § 56-8-4 judgment rate applies to delinquent spousal support, not child support. 2026 HB 266 proposed raising the child-support rate to 6.5%, but the official bill record says it died, so 4% remains operative.NMSA 1978, § 40-4-7.3 — interest on delinquent support (New Mexico Legislature) | $200.00 |
| Arrears principal plus interestNMSA 1978, § 40-4-7.3 — interest on delinquent support (New Mexico Legislature) | $5,200.00 |
Assumptions
- Accrual period expressed as 12 month(s); partial months prorate.
Estimate only. The court or state agency calculation controls.
New Mexico arrears interest under NMSA 1978, § 40-4-7.3; rules last reviewed 2026-08-25.
Monthly planning scenario
Test a New Mexico arrears payment
Estimate how a fixed monthly payment could reduce a reconciled 4% child-support balance. This is not an official payoff quote: the court or agency ledger controls every principal, interest, payment, adjustment, and posting date.
New Mexico payment-plan summary
Planning scenario only, not an official payoff quote or a change to your order. The court or agency ledger controls the balance and actual payment posting dates.
Enter ledger amounts and complete all three confirmations to see a projection.
Estimate only. The court or state agency calculation controls.
New Mexico monthly arrears planning scenario; statute and source last rechecked 2026-08-25.
Delinquent child support accrues 4% interest
Section 40-4-7.3 sets delinquent child support and consolidated child-support judgments at 4% annual interest.
The §56-8-4 judgment rate applies to spousal support instead. A 2026 proposal to raise child-support interest to 6.5% died and did not change the operative 4% rule.
Payments apply first to current support, then delinquent support and consolidated principal, then interest.
Reconcile by installment
Use this calculator for a planning projection from a principal balance, rate, and period. A real New Mexico ledger needs every installment due date, payment posting date, and consolidation event.
The monthly payment section is narrower. It runs only after you confirm that a current court or agency ledger separates principal from interest, the entire principal is subject to 4%, and current support will be paid before the entered arrears payment. It models month-end payments, principal before interest, and no new charges or adjustments.
For the enacted 4% rule, the difference from the general judgment rate, and the statutory payment order, read the linked New Mexico arrears interest explanation. For the legal balance in a case, use the agency or court ledger.
What this estimate includes
- Simple 4% child-support projection
- Confirmed-balance monthly payment scenario
- Principal-before-interest allocation after current support
What it leaves out
- Official payoff quote
- Mixed historical rate segments
- New support charges or payment-posting ledger
- Interest forgiveness or case adjustments
New Mexico arrears calculator FAQs
When does interest start?
When each support payment becomes delinquent.
What rate applies?
Four percent per year under §40-4-7.3 for delinquent child support.
What is the current statutory rate?
4% for delinquent child support.
What gets paid first?
Current support, then principal categories, then accrued interest.
Can this estimate how long a monthly payment may take?
Yes, but only as a planning scenario after you confirm a reconciled principal-and-interest ledger, a 4%-eligible child-support balance, and a payment amount available after current support. The projection assumes month-end payments and is not an official payoff quote.
What if the balance includes older rates or spousal support?
Do not use the monthly payment result. The planner fails closed because mixed historical rates and the separate spousal-support rate need a dated official ledger.
Does this replace the official ledger?
No.
Does spousal support accrue too?
Yes, but §40-4-7.3 sends delinquent spousal support to the separate §56-8-4 judgment rate. This child-support calculator does not use that spousal-support rate.
Did New Mexico raise the child-support rate to 6.5% in 2026?
No. HB 266 proposed that increase, but the official legislative record says the bill died. The operative child-support rate remains 4%.
Official sources
Official sources last verified: .
- NMSA 1978, § 40-4-7.3 — interest on delinquent support
New Mexico Legislature Last checked
- 2026 HB 266 § 2 — proposed child-support interest increase (died)
New Mexico Legislature Last checked
Changelog: page reviewed . Material changes appear in the update log.