Money & Taxes
Biweekly vs. Semimonthly Child Support: Payment Math
Compare child support every two weeks with twice a month. See a $700 monthly example, rounding differences, extra paydays, and what your payroll order controls.
Updated for 2026 state guidelines
Child support calculators you can check
Child support rules are public law, but the math behind them is hard to find and easy to get wrong. This site runs the real state formulas and shows its work. Every rate, cap, and table links to an official source, with the date it took effect and the date we last checked it.
Everything here is an estimate, not legal advice. The court or state agency calculation controls.
Choose your state
Open the current formula, source notes, worked example, and official links for your jurisdiction.
Popular state calculators
- Florida child support calculator
- Texas child support calculator
- North Carolina child support calculator
- Oregon child support calculator
- Oklahoma child support calculator
- New Jersey child support calculator
- Minnesota child support calculator
- California child support calculator
- New York child support calculator
- Ohio child support calculator
- Maryland child support calculator
Compare child support rules and verification evidence on the US map →
Popular custody schedules
Start here
Child support calculatorSee which guideline model all 50 states and DC use, compare a standard scenario across them, and run a full estimate for any of the 51 jurisdictions.Open the calculator →Start with your situation
Not sure which calculator you need? Pick what is happening and follow a short path through the relevant tool, explanation, and official source.
- Starting a child support caseUnderstand the guideline model, estimate a range, and find the official agency for your state.
- My income changedLearn what can affect a review, then compare a fresh estimate without changing the existing order.
- The other parent missed paymentsSee how arrears and interest rules differ, then open the calculator for the state that controls.
- We share parenting timeCount the actual overnights first, then see how your state treats shared or equal schedules.
- One parent has high incomeCheck whether the state uses a ceiling, a floor, an add-on, or court discretion above the table.
- Planning a custody scheduleCompare common rotations, put one on a real calendar, count overnights, and add holidays.
- Who claims the child on taxesSee the credit value at stake and read the federal rules without treating a calculator as an eligibility decision.
- Understanding wage withholdingEstimate the legal withholding ceiling and compare the federal tiers with the rule in your state.
State calculators
All 51 jurisdictions have full research packs: the current formula, the current tables, a worked example, and the quirks that trip people up. Each jurisdiction carries four tools: child support, arrears and interest, wage garnishment limits, and alimony or spousal support.
Coverage includes all 50 states plus Washington, DC. Each research pack is reviewed against official worksheets and primary legal sources.
51
Jurisdictions mapped: 50 states plus DC
51
Jurisdictions with full calculators: support, arrears, garnishment, alimony
491
Official sources cited, each with a checked date
510
Test scenarios run through the real formulas on every build; 58 match official calculators within the published verification tolerance
Parenting time and money tools
Overnights drive many support formulas, so the schedule tools and the money tools share the same math. All of them run in your browser; nothing you type is stored or sent anywhere.
- Parenting time calculatorCount overnights for 10 common schedules and see the true percentage split.Open the tool →
- Custody schedule generatorLay a rotation over a real calendar and download it as a free .ics file.Open the tool →
- Custody schedule libraryTen patterns like 2-2-3 and week on week off, each with day-by-day math.Open the tool →
- Holiday schedule builderLayer 12 holidays like Thanksgiving and winter break over any rotation.Open the tool →
- Expense split calculatorDivide childcare, medical, and school costs in proportion to income.Open the tool →
- Who claims the child on taxesWhat the 2026 Child Tax Credit is worth and how Form 8332 moves the claim.Open the tool →
- Guides libraryTen short guides to the formulas, income rules, and schedule math.Open the tool →
- High-income child support capsWhat happens above the guideline ceiling in 6 states with newly effective caps.Open the tool →
- Child support by incomeWhat $500 to $2,000 a week looks like in 38 states, shown as scenarios, not one number.Open the tool →
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School-Year vs. Summer Custody Schedules: A Dated Example
Compare continuing a school-week routine with alternating summer weeks on the same dates. Count changed nights and plan the transition back without gaps.
How we keep the numbers honest
A number without a source is a guess. Ours come from statutes, court rules, and official guideline tables, and each page lists exactly which ones. When a state has no formula, we say so instead of inventing one. When a rule changes, the fix gets a dated entry in the update log, never a silent edit.
The formulas are also regression-tested: 510 scenarios run through the real state formulas on every build, 58 of them match official calculator outputs within the published verification tolerance, and 156 still await an official cross-check. We publish that pending count instead of claiming universal accuracy.