The basics

Family Code section 4055(b)(7) gives the paying parent (the obligor) a rebuttable presumption in favor of a low-income adjustment, or LIA, whenever their monthly net disposable income comes in under full-time minimum wage. When it applies, the adjustment trims the support amount the guideline formula would otherwise produce. “Rebuttable” matters here: the presumption is the starting point, not the last word, and a judge can land somewhere else with a reason.

Where the 2026 threshold comes from

Since September 1, 2024, the threshold has been pegged to the monthly gross income of a full-time minimum-wage job, figured at 40 hours a week for 52 weeks. With minimum wage at $16.90 an hour under Labor Code section 1182.12 (effective January 1, 2026), that math is:

$16.90 x 40 hours x 52 weeks / 12 months = $2,929/month

Before September 2024 the number worked differently, adjusted each year against the California Consumer Price Index.

How the reduction is calculated

The adjustment scales with how far below the line you fall. The further under the threshold the obligor’s net sits, the bigger the cut:

Reduction = guideline amount x (threshold - obligor net) / threshold

Take a guideline amount of $500 a month and an obligor net of $2,000:

  • Reduction = $500 x ($2,929 - $2,000) / $2,929 = $500 x 0.317 = $159
  • Adjusted range: $341 to $500

The court can order anywhere in that range, or rebut the presumption entirely if the facts call for it.

It’s net income, not gross

This is the detail that catches people out. The $2,929 line applies to net disposable income, which is what’s left after taxes, FICA, health insurance, and the other deductions allowed under FC section 4059. Gross pay can sit well above the threshold while net slips below it. A parent grossing $4,000 a month can easily land under $2,929 net once the deductions come off.

How the calculator handles it

The Support Split calculator checks the obligor’s net against the threshold on every run and applies the LIA when it qualifies, then shows whether the adjustment kicked in and what the adjusted range looks like. That link opens a low-income example so you can see it in action.

For the official figures, the Judicial Council of California publishes the current LIA threshold along with the historical amounts going back to 1994.