New Mexico Child Support 2026: Income Shares and the 35% Rule

Income Shares Model: How New Mexico Combines Both Parents' Income

New Mexico calculates child support under the Income Shares model, codified in NMSA 1978 § 40-4-11.1. The premise is that a child should receive the same proportion of combined parental income they would have received if the household had stayed together. Unlike the Percentage of Income model used in states like Texas, New Mexico requires both parents' incomes to determine the baseline obligation.

The starting point is gross monthly income — not take-home pay. New Mexico defines gross income broadly. It includes wages, salaries, commissions, bonuses, self-employment income, rental income, investment dividends, interest, trust income, pensions, Social Security benefits (excluding SSI), workers' compensation, disability benefits, and unemployment compensation. If you receive regular income from any source, it almost certainly counts.

Adjusted gross income applies specific deductions before plugging into the guideline table. Allowable deductions include court-ordered child support already being paid for children from other relationships, court-ordered alimony currently being paid, and the cost of work-related childcare for the child at issue in the current case. Health insurance premiums paid for the children in the case are added separately as a line item rather than deducted from gross income. They increase the total obligation proportionally.

Self-employment income requires extra calculation. New Mexico uses net income from self-employment after ordinary business expenses — but not after depreciation taken for tax purposes unless it reflects actual asset value loss. Courts scrutinize self-employment returns carefully because of the latitude to shift personal expenses to business deductions.

Once both parents' adjusted gross incomes are calculated, they are added together to create the combined monthly adjusted gross income. This combined figure is then used to look up the basic child support obligation (BSO) in the New Mexico guideline table. The table produces a single dollar amount for a given number of children at a given combined income level.

The 35% Rule: Why Overnight Time Changes Everything in New Mexico

New Mexico divides its child support calculation into two worksheets based on how much overnight time the noncustodial parent exercises. The dividing line is 35% of annual overnights — which equals approximately 128 nights per year (365 × 0.35 = 127.75).

Worksheet A applies when the noncustodial parent has fewer than 128 overnights per year. This is the standard calculation: the noncustodial parent's share of the combined income determines their share of the basic support obligation, plus their proportionate share of childcare and health insurance costs.

Worksheet B applies when each parent has at least 35% of overnight time — meaning the noncustodial parent has 128 or more overnights annually. In this scenario, New Mexico multiplies the basic support obligation by 1.5 before dividing it proportionally between the parents. Both parents' obligations are then calculated, and the lower earner's obligation is subtracted from the higher earner's, with the higher earner paying the difference.

Why the 1.5 multiplier? The theory is that when both parents maintain a primary household for the child, both incur duplicated fixed costs — beds, bedrooms, clothing, food supplies. The multiplier accounts for these dual household expenses that don't exist in a primary-custody arrangement.

Worked example — same facts, two scenarios:

Parent A gross income: $6,000/month Parent B gross income: $3,500/month Combined: $9,500/month Two children

Parent A's income share: $6,000 ÷ $9,500 = 63.2% Parent B's income share: $3,500 ÷ $9,500 = 36.8%

Basic Support Obligation from NM table for $9,500 combined / 2 children: approximately $1,580/month

Worksheet A (Parent A has 100 overnights — fewer than 128): Parent A owes: $1,580 × 63.2% = $998/month

Worksheet B (Parent A has 130 overnights — 128 or more): Adjusted BSO: $1,580 × 1.5 = $2,370 Parent A's share: $2,370 × 63.2% = $1,498 Parent B's share: $2,370 × 36.8% = $872 Net payment (Parent A to Parent B): $1,498 − $872 = $626/month

The difference between 100 nights and 130 nights is not $37.50/month. It is $372/month — and that gap compounds over years of an order. For parents mediating parenting plans, the financial implication of crossing the 128-night threshold is often larger than any income adjustment either side can negotiate.

SB 223: What Changed in 2024 and Why It Still Matters in 2026

New Mexico enacted Senate Bill 223, which became effective January 1, 2024. As of 2026, these are the operative guidelines — no further updates have superseded them.

The most significant change was expanding the basic child support schedule. Prior to SB 223, the guideline table topped out at a lower combined income figure. Under SB 223, the schedule now covers combined monthly incomes up to $30,000. Parents with combined incomes above $30,000 are still subject to child support, but the calculation requires judicial discretion rather than a table lookup — the $30,000 figure is the ceiling of the schedule, not an income cap for support itself.

The $1,200 self-support reserve is the second major addition. When the noncustodial parent's net income (after taxes and mandatory deductions) falls below $1,200 per month, the guideline obligation is automatically reduced. The court does not eliminate support entirely, but the order must reflect that the paying parent retains at least $1,200 per month for their own subsistence. This protects low-income parents from support orders that would make it impossible to maintain housing and basic necessities.

The self-support reserve is a rebuttable presumption, not an absolute floor. A court can deviate from the guideline if specific circumstances — such as the receiving parent's extreme need or the paying parent's hidden assets — make strict application inequitable. But deviation requires written findings on the record explaining why the presumption was overcome.

Courts applying SB 223 in 2026 use the updated table directly. If you have an older order calculated under pre-2024 guidelines, the table change itself is not automatically a basis for modification — you would still need to show a material and substantial change in circumstances. But if other factors have also changed (job loss, income increase, new children), the updated table produces the recalculated baseline.

Step-by-Step: Calculating Your New Mexico Child Support

Follow these steps before any mediation session or court hearing on child support.

Step 1 — Determine gross monthly income for each parent. Add all sources: wages, self-employment net, rental income, benefits. For irregular income like commissions or seasonal work, courts typically average the last 12 to 24 months.

Step 2 — Apply allowable deductions. Subtract court-ordered support currently being paid for other children or current alimony obligations. Do not subtract voluntary expenses, personal loans, or mortgage payments.

Step 3 — Add both adjusted gross incomes to get combined monthly income.

Step 4 — Look up the basic support obligation in the SB 223 table using combined income and number of children. If combined income exceeds $30,000, the table does not directly apply — the court sets the amount based on the 13 statutory factors in § 40-4-11.1.

Step 5 — Determine each parent's income share percentage (each parent's income ÷ combined income).

Step 6 — Count overnights. If the noncustodial parent has fewer than 128 nights per year, use Worksheet A. If 128 or more, use Worksheet B.

Worksheet A: Noncustodial parent's obligation = BSO × noncustodial parent's income share percentage Add proportionate share of work-related childcare costs and health insurance premiums.

Worksheet B: Adjusted BSO = BSO × 1.5 Each parent's preliminary obligation = Adjusted BSO × their income share percentage Net payment = higher earner's obligation − lower earner's obligation The higher-earning parent pays the difference.

Step 7 — Check the self-support reserve. If the paying parent's net monthly income is below $1,200, the obligation may be reduced.

Step 8 — Open [TheLegalCalc's New Mexico child support calculator](/child-support-calculator/new-mexico) to model different income and parenting time scenarios before finalizing a parenting plan or making a modification request.

The $1,200 Self-Support Reserve: Protection for Low-Income Parents

The self-support reserve under SB 223 prevents New Mexico courts from setting child support so high that the paying parent cannot meet their own basic needs. The threshold is $1,200 per month in net income — after federal and state income taxes, Social Security, and Medicare are deducted from gross.

How it works in practice: if a paying parent earns $1,500/month gross and has net income of approximately $1,300/month after taxes, a guideline calculation that would otherwise produce a $600/month order would be reviewed against the reserve. The court would not automatically impose $600 when doing so would leave the parent with only $700 for all living expenses. The order would likely be reduced — the exact amount depends on the specific circumstances, but the reserve sets a floor at $1,200 net retained.

What the reserve does not do: it does not eliminate the obligation. Courts still enter orders for low-income parents, often at a nominal amount (sometimes as low as $50–$100/month) to establish the legal record and allow for modification when income changes. A nominal order preserves the child's right to support and the state's ability to modify upward when circumstances improve.

Who qualifies: the reserve applies when the paying parent's net — not gross — monthly income falls below $1,200. A parent earning $15/hour at 40 hours/week ($2,600/month gross) typically has net income well above $1,200 and does not qualify. A part-time or seasonal worker, or someone earning minimum wage, may qualify. Courts also consider whether low income is voluntary — imputed income can override the reserve if the court finds willful underemployment.

Documentation matters: if you are claiming the reserve applies to your situation, bring pay stubs, tax returns, and a monthly budget to show net income and actual living expenses. Asserting the reserve without documentation rarely succeeds in New Mexico courts.

What Counts as Income in New Mexico

New Mexico's definition of income for child support purposes is intentionally broad. Courts are directed to include all income from whatever source derived, with specific exceptions for means-tested public assistance.

Income that counts: Wages, salary, tips, and overtime. All pre-tax earnings from employment, regardless of whether the employer is large or small or whether you are paid hourly or salaried.

Self-employment income. Net profit after legitimate business expenses — not after depreciation unless it reflects genuine economic loss. Courts frequently request multiple years of Schedule C or business returns to identify expense manipulation.

Rental property income. Gross rents minus actual maintenance, mortgage interest, taxes, and insurance paid on the rental property. Depreciation deductions for tax purposes are generally not subtracted.

Investment and passive income. Dividends, capital gains distributions, interest, and income from limited partnerships.

Benefits. Social Security retirement benefits, disability benefits (SSDI), pensions, veterans' benefits, workers' compensation, and unemployment compensation all count.

Income that does not count for guidelines purposes: TANF and SNAP benefits are specifically excluded. SSI payments are excluded. Child support received for other children is not counted as income for the parent receiving it in this case.

Imputed income: when a parent is willfully underemployed or unemployed, the court may attribute income based on earning capacity rather than actual income. New Mexico courts look at education, work history, local job market, and available jobs. The minimum floor for imputed income is the applicable minimum wage at 40 hours per week. A parent who voluntarily leaves a $60,000/year job cannot simply declare $0 income for child support purposes. The burden falls on the imputing party to show the underemployment is voluntary.

Modifying Child Support in New Mexico

New Mexico allows modification of child support when there is a "material and substantial change in circumstances." Unlike some states that specify a percentage threshold (Texas uses 20% or $100/month), New Mexico's standard is deliberately discretionary — courts have latitude to determine what qualifies.

What typically constitutes a material and substantial change in New Mexico: A significant change in either parent's income — job loss, promotion, disability, or new employment. Courts apply common sense: a 5% raise is unlikely to qualify; losing a job entirely almost certainly does.

A change in parenting time that crosses the 128-night threshold in either direction. A parent who gains enough overnights to trigger Worksheet B has grounds to seek modification. A parent who loses overnights and drops below the threshold likewise has grounds.

A change in the child's needs — new medical expenses, change in childcare costs, or a child aging out of daycare.

A significant change in health insurance costs for the children.

Three-year review: New Mexico also allows either parent to request a review every three years even without showing a specific material change. The state's child support enforcement agency (CYFD) offers this service for existing orders. This review applies the current guidelines to current incomes and may result in an adjusted order.

Arrears collection — the 14-year rule: New Mexico allows collection of child support arrears for 14 years after each individual payment was due. This is measured from the due date of each missed payment, not from the date of the court order. A payment that was due on March 1, 2018 can be collected until approximately March 1, 2032. This is notably longer than most states' collection windows and means that old arrears balances do not disappear quickly. Parents with accrued arrears should not assume that time has resolved the obligation.

Enforcement: New Mexico's "25 Most Wanted" List and License Suspensions

New Mexico's child support enforcement operates through the Children, Youth and Families Department (CYFD) and the New Mexico Child Support Enforcement Division (CSED). The state uses a range of tools — some of which are unusual in scope.

The "25 Most Wanted" program: New Mexico publishes a list of the 25 parents with the highest outstanding child support arrears who are actively evading collection. This is a public-facing initiative, meaning names and photos of obligors with large unpaid balances appear on state websites and in press releases. The program is designed both to locate non-paying parents and to create social and professional consequences for evasion. New Mexico is one of the few states with such a program.

License suspensions: CSED can suspend a non-paying parent's driver's license, professional licenses, hunting and fishing licenses, and recreational vehicle licenses when child support payments fall significantly behind. License suspension is one of the most effective enforcement tools because it disrupts employment and daily life without requiring a separate court hearing in all cases. Reinstatement requires bringing the account current or entering into an approved payment plan.

Income withholding: all new child support orders in New Mexico include immediate income withholding, meaning the employer deducts support directly from wages before the parent receives their paycheck. This is the primary collection mechanism for employed parents.

Other enforcement tools include federal and state tax refund intercepts, bank account levies, liens on real and personal property, passport denial for arrears exceeding $2,500, and contempt of court proceedings that can result in jail time.

For current enforcement status or to report a non-paying parent, contact [New Mexico CSED at childsupport.nm.gov](https://www.childsupport.nm.gov).

Use the Calculator — Then Review the Official Worksheets

TheLegalCalc's [New Mexico child support calculator](/child-support-calculator/new-mexico) applies the Income Shares model under § 40-4-11.1 with SB 223 updates. It calculates both Worksheet A and Worksheet B scenarios so you can model the impact of different parenting time arrangements before finalizing a parenting plan.

Before any court hearing or mediation, also review:

The official New Mexico child support worksheets — available from the New Mexico Judiciary (nmcourts.gov). Courts require the actual worksheets in filings, not calculator printouts, but our calculator output gives you the numbers to plug in.

New Mexico CYFD child support services at [childsupport.nm.gov](https://www.childsupport.nm.gov) for enforcement services, payment history, and modification requests through the agency.

Bring to court: two years of tax returns, current pay stubs, documentation of all income sources, childcare invoices, health insurance premium statements, and the current parenting schedule showing overnight counts.

New Mexico Legal Aid (nmlegalaids.org) offers family law resources for parents who cannot afford private counsel. Self-represented litigants in child support matters have access to the Judiciary's self-help centers in Bernalillo, Doña Ana, and Santa Fe counties.