Child Custody & Support
When parents split up, state law decides who the child lives with, how decisions get made, and how much child support is paid. Almost every state uses the same north star — the “best interests of the child” — but the support formula, the age support ends, and any preference for shared parenting differ by state.
Know your options
- Custody has two parts: “Legal custody” is who makes the big decisions (school, medical, religion); “physical custody” is where the child lives. Either can be shared (joint) or given mainly to one parent.
- Best interests is the standard: Judges weigh the child’s safety and stability, each parent’s involvement, and (for older kids) the child’s wishes. Some states now start from a presumption of roughly equal 50/50 parenting time.
- Support follows a formula: Every state uses guidelines — most an “income shares” model (both parents’ incomes), a few a flat percentage of the paying parent’s income. Sharing time doesn’t always erase support.
- Which state decides: Under a nationwide law (the UCCJEA), the child’s “home state” — where they’ve lived the last 6 months — controls custody, and it keeps that power as long as a parent or the child still lives there.
Your state’s rules
Pick your state above to see your rules.
Alabama
- Custody standard
- Best interests of the child.
- Child-support formula
- Income-shares model (Rule 32), with a shared-custody adjustment for 50/50 time.
- When support ends
- Age 19 — Alabama’s age of majority.
- Changing an order
- A material change producing a 10%+ difference from the current order.
Alaska
- Custody standard
- Best interests of the child.
- Child-support formula
- Percentage of the paying parent’s adjusted income (Civil Rule 90.3): 20% (1 child), 27% (2), 33% (3)…
- When support ends
- Age 18 (or up to 19 if still in high school).
- Changing an order
- A 15%+ change in the support amount is presumed material.
Arizona
- Custody standard
- Best interests, across 11 factors (A.R.S. § 25-403). Arizona uses “legal decision-making” + “parenting time.”
- Child-support formula
- Income-shares model — both parents’ incomes and each one’s parenting time.
- When support ends
- Age 18 (or up to 19 if still in high school).
- Changing an order
- A substantial and continuing change in circumstances.
Arkansas
- Custody standard
- Best interests of the child.
- Child-support formula
- Income-shares model (adopted 2020) — both parents’ incomes, split by share.
- When support ends
- Age 18 (or high-school graduation, not past 19).
- Changing an order
- A 20%+ guideline difference is presumed a material change.
California
- Custody standard
- Best interests of the child; no automatic preference for either parent. Joint custody is common but not presumed.
- Child-support formula
- Guideline “income shares” formula — both parents’ incomes and each one’s share of parenting time (Family Code § 4055).
- When support ends
- Age 18 (or 19 if still a full-time high-school student living at home).
- Changing an order
- Show a change in circumstances; support can be revisited whenever the guideline result would differ.
Colorado
- Custody standard
- Best interests. Colorado uses “allocation of parental responsibilities,” not custody (since 1998).
- Child-support formula
- Income-shares model — every overnight counts toward the calculation (2026 reform).
- When support ends
- Age 19 (earlier if the child marries or becomes self-supporting).
- Changing an order
- A change producing a 10%+ difference in the support amount.
Connecticut
- Custody standard
- Best interests of the child.
- Child-support formula
- Income-shares model (a “baseline budget” split by each parent’s income).
- When support ends
- Age 18 (or 19 if a full-time high-school student).
- Changing an order
- A substantial change; a 15%+ guideline difference is presumed.
Delaware
- Custody standard
- Best interests of the child.
- Child-support formula
- Modified “Melson” formula — each parent keeps ~$1,570/month for self-support first, then a standard-of-living adjustment.
- When support ends
- Age 18 (or up to 19 if still in high school).
- Changing an order
- A substantial change; either parent can seek a review after 2½ years regardless.
Florida
- Custody standard
- Best interests; since 2023 a rebuttable presumption of 50/50 equal time-sharing (Florida uses “time-sharing,” not “custody”).
- Child-support formula
- Income-shares model — both parents’ net incomes and the overnights each has (Fla. Stat. § 61.30).
- When support ends
- Age 18 (up to 19 if still in high school and on track to graduate).
- Changing an order
- A substantial, material change; a support recalculation must differ by at least 15% or $50.
Georgia
- Custody standard
- Best interests of the child; a child 14+ can choose which parent to live with (subject to the judge).
- Child-support formula
- Income-shares model — both parents’ incomes combined and split by share.
- When support ends
- Age 18 (or up to 20 if still in high school).
- Changing an order
- A material change; either parent may seek review once every 2 years.
Hawaii
- Custody standard
- Best interests of the child.
- Child-support formula
- Modified “Melson” formula — protects each parent’s basic needs first, then adds a standard-of-living adjustment (one of only 3 Melson states).
- When support ends
- Age 18 (19 if in high school); can extend to 23 for a full-time college student.
- Changing an order
- A substantial change; a 10%+ recalculation is presumed substantial.
Idaho
- Custody standard
- Best interests of the child.
- Child-support formula
- Income-shares model (with a 1.5× bump when each parent has 25%+ of the overnights).
- When support ends
- Age 18 (or up to 19 if still in high school).
- Changing an order
- A substantial and material change — a 15%+ income change qualifies.
Illinois
- Custody standard
- Best interests (17 factors). Illinois uses “allocation of parental responsibilities” + “parenting time,” not the word custody.
- Child-support formula
- Income-shares model — both parents’ net incomes, split by share (a 1.5× adjustment when parenting time is roughly equal).
- When support ends
- Age 18 (or high-school graduation, up to 19).
- Changing an order
- A substantial change in circumstances since the last order.
Indiana
- Custody standard
- Best interests; no presumption for either parent (IC 31-17-2-8).
- Child-support formula
- Income-shares model (weekly gross incomes, split by share).
- When support ends
- Age 19 (Indiana ends support earlier than most states).
- Changing an order
- A substantial change, or a 20%+ difference from the current order.
Iowa
- Custody standard
- Best interests of the child.
- Child-support formula
- Income-shares model (Iowa Court Rules ch. 9).
- When support ends
- Age 18 (or up to 19 if still in high school).
- Changing an order
- A substantial change; a 10%+ variation is substantial as a matter of law.
Kansas
- Custody standard
- Best interests of the child.
- Child-support formula
- Income-shares model (both incomes, with age brackets 0–5, 6–11, 12–18).
- When support ends
- Age 18 (continues to June 30 if the child turns 18 during the school year).
- Changing an order
- A 10%+ difference from the current order.
Kentucky
- Custody standard
- Best interests, with a rebuttable presumption of joint custody and equal parenting time (KRS 403.270) — Kentucky was the first state to adopt this.
- Child-support formula
- Income-shares model (both parents’ incomes, split by share).
- When support ends
- Age 18 (or through the school year if still in high school, up to 19).
- Changing an order
- A 15%+ difference from the current order is presumed material.
Louisiana
- Custody standard
- Best interests of the child.
- Child-support formula
- Income-shares model (La. R.S. 9:315) — combined incomes split by share.
- When support ends
- Age 18 (or 19 if a full-time high-school student in good standing).
- Changing an order
- A material change; a 25%+ guideline difference, or a review after 3 years.
Maine
- Custody standard
- Best interests; Maine uses “parental rights and responsibilities,” not custody.
- Child-support formula
- Income-shares model (combined gross incomes, split by share).
- When support ends
- Age 18 (or up to 19 if still in high school).
- Changing an order
- A substantial change; a 15%+ guideline difference is presumed.
Maryland
- Custody standard
- Best interests of the child.
- Child-support formula
- Income-shares model (both parents’ incomes and add-ons like childcare and health insurance).
- When support ends
- Age 18 (or up to 19 if still in high school).
- Changing an order
- A material change in circumstances since the last order.
Massachusetts
- Custody standard
- Best interests of the child.
- Child-support formula
- Guidelines based on both parents’ incomes (an income-shares-style formula).
- When support ends
- Support can run to 18, and up to 21 (living at home) or 23 (in college and dependent).
- Changing an order
- A material and substantial change in circumstances.
Michigan
- Custody standard
- Best interests, across 12 statutory factors.
- Child-support formula
- Income-shares model (the Michigan Child Support Formula, using net income).
- When support ends
- Age 18 (or up to 19½ if still a full-time high-school student).
- Changing an order
- A change producing a 10% or $50/month difference; a review is allowed every 3 years.
Minnesota
- Custody standard
- Best interests of the child.
- Child-support formula
- Income-shares model — combined parental income (PICS), split by share.
- When support ends
- Age 18 (or up to 20 if still in high school).
- Changing an order
- A substantial change that makes the current order unreasonable or unfair.
Mississippi
- Custody standard
- Best interests, weighed under the 12 “Albright factors.”
- Child-support formula
- Percentage of the paying parent’s adjusted gross income: 14% (1 child), 20% (2), 22% (3)…
- When support ends
- Age 21 — one of the highest in the country.
- Changing an order
- A material change in circumstances since the last order.
Missouri
- Custody standard
- Best interests of the child.
- Child-support formula
- Income-shares model, calculated on “Form 14.”
- When support ends
- Age 18 (or 21 if the child enrolls in college by Oct. 1 after high school and stays enrolled).
- Changing an order
- A substantial and continuing change; a 20%+ Form-14 difference is presumed.
Montana
- Custody standard
- Best interests; Montana uses a “parenting plan.”
- Child-support formula
- Modified “Melson” formula — each parent keeps a self-support allowance first, then a standard-of-living adjustment (one of only 3 Melson states).
- When support ends
- Age 18 (or high-school graduation, up to 19).
- Changing an order
- A change so significant the current order is “unconscionable” (or by written agreement).
Nebraska
- Custody standard
- Best interests of the child.
- Child-support formula
- Income-shares model (combined net incomes, split by share).
- When support ends
- Age 19 — Nebraska’s age of majority.
- Changing an order
- A material change producing a 10%+ ($25 min) difference, lasting 3+ months.
Nevada
- Custody standard
- Best interests of the child.
- Child-support formula
- Percentage of income (tiered): 16% of the first $6,000/month for one child (22% for two), with lower rates on higher income; no cap.
- When support ends
- Age 18 (or 19 if still in high school).
- Changing an order
- A 20%+ income change, or a review every 3 years.
New Hampshire
- Custody standard
- Best interests of the child (RSA 461-A:6).
- Child-support formula
- Income-shares model (a percentage of combined net income — ~19–25% for one child).
- When support ends
- Age 18 (or high-school graduation, up to 19).
- Changing an order
- A 20%+ guideline difference, or a review every 3 years.
New Jersey
- Custody standard
- Best interests of the child.
- Child-support formula
- Income-shares model — both parents’ incomes combined and split by share.
- When support ends
- Age 19 by default (can extend to 23 for full-time college or disability).
- Changing an order
- A significant, permanent change in circumstances.
New Mexico
- Custody standard
- Best interests of the child.
- Child-support formula
- Income-shares model (Worksheet A for primary custody, Worksheet B for shared).
- When support ends
- Age 18 (or up to 19 if still in high school).
- Changing an order
- A 20%+ guideline difference after at least a year is presumed material.
New York
- Custody standard
- Best interests of the child; no presumption favoring either parent.
- Child-support formula
- Percentage of combined parental income (CSSA): 17% (1 child), 25% (2), 29% (3)…, on income up to $193,000 (2026).
- When support ends
- Age 21 — one of the highest in the country.
- Changing an order
- A substantial change, a 15%+ income change, or 3 years since the last order.
North Carolina
- Custody standard
- Best interests of the child; no default preference.
- Child-support formula
- Income-shares model (Worksheets A/B/C depending on the custody split).
- When support ends
- Age 18 (or up to 20 if still in high school).
- Changing an order
- A substantial change; a 15%+ guideline difference after 3 years is presumed substantial.
North Dakota
- Custody standard
- Best interests, across 13 statutory factors (NDCC § 14-09-06.2). North Dakota uses “parental responsibilities.”
- Child-support formula
- Percentage of the paying parent’s net income only — the other parent’s income doesn’t reduce it.
- When support ends
- Age 18 (or up to 19 if still in high school).
- Changing an order
- A $50+ change, or a review after 12 months.
Ohio
- Custody standard
- Best interests of the child. Ohio allocates “parental rights and responsibilities.”
- Child-support formula
- Income-shares model, with a parenting-time credit (10% for 90+ overnights).
- When support ends
- Age 18 (or high-school graduation, up to 19).
- Changing an order
- A change of circumstances — a 10%+ difference from the current order is the trigger.
Oklahoma
- Custody standard
- Best interests of the child.
- Child-support formula
- Income-shares model (43 O.S. § 118), with a parenting-time adjustment for 121+ overnights.
- When support ends
- Age 18 (or up to 20 if still in high school).
- Changing an order
- A material change — a 10%+ income change is a common trigger.
Oregon
- Custody standard
- Best interests of the child; Oregon won’t award joint custody unless both parents agree.
- Child-support formula
- Income-shares model (ORS 25.275).
- When support ends
- Age 18 (extends to 21 if the child is a full-time student).
- Changing an order
- A substantial change, or a review after ~35 months; a 15%/$50 difference qualifies.
Pennsylvania
- Custody standard
- Best interests, weighed across 16 statutory factors (23 Pa.C.S. § 5328); no default preference.
- Child-support formula
- Income-shares model — combined incomes set the obligation, then split by each parent’s share.
- When support ends
- Age 18 (or high-school graduation, whichever is later).
- Changing an order
- A material and substantial change in circumstances since the last order.
Rhode Island
- Custody standard
- Best interests, weighed under the 8 “Pettinato factors.”
- Child-support formula
- Income-shares model (combined adjusted gross incomes, split by share).
- When support ends
- Age 18 (or up to 19 if still in high school).
- Changing an order
- A substantial change in circumstances since the last order.
South Carolina
- Custody standard
- Best interests, across 17 factors (S.C. Code § 63-15-240).
- Child-support formula
- Income-shares model — both parents’ incomes combined and split by share.
- When support ends
- Age 18 (or through the school year after the child turns 19 if still in high school).
- Changing an order
- A substantial change; a 15%+ guideline difference is presumed substantial.
South Dakota
- Custody standard
- Best interests of the child.
- Child-support formula
- Income-shares model (combined net incomes, split by share).
- When support ends
- Age 18 (or up to 19 if still a full-time high-school student).
- Changing an order
- A substantial change; a 20%+ difference qualifies.
Tennessee
- Custody standard
- Best interests (17 factors, TCA 36-6-106). Tennessee names a “primary residential parent.”
- Child-support formula
- Income-shares model — both parents’ incomes and their parenting days.
- When support ends
- Age 18 (or high-school graduation, up to 19).
- Changing an order
- A 15% difference from the current order (7.5% for low-income cases).
Texas
- Custody standard
- Best interests; Texas presumes “joint managing conservatorship” (shared decision-making) in most cases.
- Child-support formula
- Percentage of the paying parent’s net resources: 20% (1 child), 25% (2), 30% (3)… capped at $11,700/month of net resources (2025).
- When support ends
- Age 18 (or when the child graduates high school, whichever is later).
- Changing an order
- A “material and substantial change,” or a 3-year review if the guideline amount would differ by 20% or $100.
Utah
- Custody standard
- Best interests of the child.
- Child-support formula
- Income-shares model (both parents’ adjusted incomes).
- When support ends
- Age 18 (or high-school graduation, up to 19).
- Changing an order
- A substantial change plus a 15%+ guideline difference (or a 10% adjustment on review).
Vermont
- Custody standard
- Best interests; Vermont uses “parental rights and responsibilities.”
- Child-support formula
- Income-shares model (combined available incomes, split by share).
- When support ends
- Age 18 (or high-school graduation, up to 19).
- Changing an order
- A “real, substantial, and unanticipated” change of circumstances.
Virginia
- Custody standard
- Best interests of the child; no preference between parents.
- Child-support formula
- Income-shares model (Va. Code § 20-108.2).
- When support ends
- Age 18 (or up to 19 / high-school graduation if a full-time student living at home).
- Changing an order
- A material change — a 25%+ income change is generally considered material.
Washington
- Custody standard
- Best interests; Washington uses a “parenting plan” instead of custody labels.
- Child-support formula
- Income-shares model (the state Economic Table; income cap raised in 2026).
- When support ends
- Age 18 (or 19 if still in high school; can extend to 23 for postsecondary school).
- Changing an order
- A substantial change of 25% or $50/month; a review is allowed after 24 months.
West Virginia
- Custody standard
- Best interests of the child.
- Child-support formula
- Income-shares model (combined gross incomes, split by share).
- When support ends
- Age 18 (or up to 20 if still in high school).
- Changing an order
- A 15%+ guideline difference is a substantial change.
Wisconsin
- Custody standard
- Best interests; Wisconsin uses “legal custody” + “physical placement.”
- Child-support formula
- Percentage-of-income standard: 17% (1 child), 25% (2), 29% (3)… of the payer’s income (adjusted for shared placement).
- When support ends
- Age 18 (or 19 if still in high school).
- Changing an order
- A substantial change: a 15%/$50 difference, or 33 months since the last order.
Wyoming
- Custody standard
- Best interests of the child.
- Child-support formula
- Income-shares model (combined net incomes, split by share).
- When support ends
- Age 18 (or up to 20 if still in high school).
- Changing an order
- A 20%+ guideline difference is presumed material.
Educational only — not legal advice. Laws change; confirm the current rule with the linked official source before you rely on it.
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