Which State Child Support Calculator Applies When Parents Live in Different States in 2026?

If you live in Texas and your co-parent lives in California, which state child support calculator applies in 2026? This is the #1 question for military families, remote workers, and parents who move after divorce. The answer is not where the child lives now, but which state has Continuing Exclusive Jurisdiction under UIFSA and UCCJEA. Using the wrong state calculator can mean $400+ per month difference. This guide explains exactly which state law controls and how to calculate correctly on SupportCalcUSA.com.

Why Interstate Child Support Is Confusing in 2026

Child support is state law, not federal. Texas uses Percentage Model with $9,200 net resources cap in 2026, California uses Income Shares with K-factor 1.0 and timeshare percentage, Florida uses Income Shares with gross-up method for 73+ nights. If mom lives in Texas and dad lives in Florida, which model applies? Many parents use the wrong calculator at https://supportcalcusa.com/ and get an incorrect estimate that a judge will reject.

Two federal laws control: UIFSA (Uniform Interstate Family Support Act) decides which state can set and modify the support amount, and UCCJEA (Uniform Child Custody Jurisdiction and Enforcement Act) decides which state can decide custody and parenting time that affects the amount. Both were updated for remote work cases in 2024-2025.

UIFSA Rule: Which State Can Set or Modify Child Support

Original Order – Home State Has Continuing Exclusive Jurisdiction

Under UIFSA Section 205, the state that issued the first child support order keeps Continuing Exclusive Jurisdiction (CEJ) as long as one parent or the child still lives there. Example: Divorce in Ohio, mom moves to Texas, dad stays in Ohio. Ohio keeps CEJ. You must use the Ohio child support calculator, not Texas, even if child now lives in Texas. Calculate at Ohio Child Support Calculator for accurate Ohio guidelines.

Outbound Authority: See official Texas rules for jurisdiction at Texas Attorney General Child Support Division https://www.texasattorneygeneral.gov/child-support and portal https://childsupport.oag.texas.gov/ for how Texas registers out-of-state orders.

Both Parents Leave Original State – New State Can Take Over

If both parents and the child all leave the original state, CEJ ends. The new state where the child lives 6 months becomes the new home state and can modify. Example: Order in New York, mom moves to Florida, dad moves to Georgia, child lives in Florida 7 months. Florida now has jurisdiction. Use Florida calculator: Florida Child Support Calculator . Florida applies 61.30 guidelines with 73+ nights gross-up rule.

No Existing Order – Where to File First Matters

If no order exists yet, you can file in either parent’s state where UIFSA personal jurisdiction exists. Most attorneys file in the state with higher support for custodial parent or lower for noncustodial. California guideline is often higher than Texas due to no cap. Compare estimates: Check California calculator at https://supportcalcusa.com/california-child-support-calculator/ versus Texas calculator at https://supportcalcusa.com/texas-child-support-calculator/ before filing. Filing first often locks jurisdiction.

UCCJEA Rule: How Custody Affects Your Calculation

UCCJEA decides parenting time credits. If Texas has custody jurisdiction but Florida has support jurisdiction, you still use Florida formula but Texas custody order determines overnights. Example: Child lives in Texas, but support order is from California. California K-factor and timeshare still apply, but Texas custody order provides overnight count. This split is common for military families.

California Department of Child Support Services explains interstate cases at https://childsupport.ca.gov/ and application at https://childsupport.ca.gov/apply-for-child-support/ for how California registers Texas orders under UIFSA.

How to Calculate Correctly on SupportCalcUSA for Interstate Cases

Step 1: Find which state has CEJ. Look at your last order header. Step 2: Use THAT state’s calculator on SupportCalcUSA.com, not where you live now. Step 3: Enter income from both states (cost of living does not change calculation, only income). Step 4: Enter custody overnights from current custody order, even if from different state. Step 5: Add health insurance and childcare actual costs.

Example: Dad in Texas $5,000 net, Mom in California $3,000, child lives in Texas but order is from California. Use California calculator: https://supportcalcusa.com/california-child-support-calculator/ . California will combine $8,000 gross, apply K-factor, timeshare. Result ~$890. If you incorrectly used Texas calculator https://supportcalcusa.com/texas-child-support-calculator/ , you would get 20% of $5,000 = $1,000 but miss California timeshare credit, wrong by $110.

Common Mistakes Parents Make When Moving

Mistake 1: Using new state calculator immediately after moving. You must wait until CEJ transfers or register order. Mistake 2: Not registering out-of-state order. You must register in new state via UIFSA. Mistake 3: Thinking child support stops when you move. It continues until new order modifies it. Mistake 4: Not updating income when cost of living changes. Texas $9,200 cap stays even if you move to high-cost California.

What Documents You Need for Interstate Modification

For accurate estimate, collect: Last child support order showing issuing state, proof of 6-month residency for child (school records, lease), income proof from both states (W-2, 1099), current custody order showing overnights, and UIFSA registration forms. Courts request 12 months income history.