Child Support Calculator 2026
Estimate child support or child maintenance payments based on official guidelines — for the United States (all 50 states), Canada, UK, Australia, and New Zealand. Free, no sign-up.
By Sammy S. · Founder · AuthorUpdated for 2026
Choose your country
United States
Income Shares ModelAll 50 states, state-specific guidelines
Canada
Federal GuidelinesFederal Guidelines & Quebec Model
United Kingdom
CMS FormulaChild Maintenance Service 6-step
Australia
8-Step FormulaServices Australia official formula
New Zealand
IRD FormulaInland Revenue formula assessment
Estimates only — not legal advice. Courts make final determinations. Consult a family law attorney.
Child Support Calculator
Enter details to estimate payments
State-specific guidelines apply. Calculations may vary by state.
Parent A's custody %. Parent B calculated automatically.
California · Income Shares
Estimated Child Support
Weekly
$30
Biweekly
$60
Monthly
$131
Annual
$1,566
Income & custody split
Calculation breakdown
State details
Guideline: California Family Code §§ 4050–4076 (Income Shares)
Updated: 2026 · Official source
Courts may deviate from guidelines for shared custody (50/50), high income exceeding caps, or special circumstances.
Recalculate if income changes by about 15–20% or more.
Shared custody can lower the paying parent's obligation.
This is an estimate only — courts make the final order.
Child support is generally not tax deductible or taxable income.
Add-ons like childcare, insurance, or medical costs can raise the total.
High-income cases above guideline caps often use court discretion.
Verify amounts with the official calculator for your location.
Consider a family law professional before relying on any estimate.
Estimate only — not a court order.
Key facts
Who should use this?
- Parents estimating support before separation
- Parents with existing orders considering modification
- Non-custodial parents planning monthly budgets
- Custodial parents checking guideline compliance
- Mediators and family law professionals
- Anyone comparing support across states or countries
US Child Support Calculator by State
Click any state for guidelines and estimates tailored to your state.
Canada Child Support Calculator by Province
Federal Child Support Guidelines for all provinces and territories. Quebec uses its own model.
What every parent needs to understand about child support
The formula is just the starting point. Understanding how it actually works saves money and reduces conflict.
Every country uses a different formula — and the differences are substantial
The US Income Shares Model takes both parents' gross income, finds a "basic support obligation" from state-specific tables (which reflect research on what intact families actually spend on children), then splits that obligation proportionally by income. A parent who earns 60% of the combined income pays 60% of the basic obligation. Additional expenses like health insurance and childcare are typically split the same way and added on top.
🇺🇸 US — Income Shares (most states)
Combined income → state table → split by income ratio. Texas and Wisconsin use Percentage of Income: a flat percentage of the paying parent's income only (20% for 1 child in TX, up to 40% for 5+).
🇨🇦 Canada — Federal Guidelines
Table-based amounts set by province and paying parent's income only. Quebec uses its own formula considering both incomes and custody time. Section 7 expenses (childcare, medical) shared proportionally.
🇬🇧 UK — CMS 6-Step Formula
Based on paying parent's gross weekly income in bands: Nil (under £7/wk), Flat, Reduced, Basic (12-19%), Basic Plus. Shared care nights (52+) reduce payments by a fixed percentage.
🇦🇺 Australia — 8-Step Formula
Calculates each parent's Child Support Income (income minus self-support amount), determines care-to-cost percentage conversion, applies Costs of Children Table by income bracket and children's ages.
New Zealand uses the IRD formula: (Income % − Care Cost %) × Child Expenditure. It deducts a living allowance (~NZD$29,909), uses Child Expenditure Tables by income and age, and requires 28% care for recognition — 35% to actually receive payments.
Shared custody changes the math — but the threshold varies widely by country
Every country recognizes that when a non-custodial parent spends meaningful time with a child, their out-of-pocket costs increase and the custodial parent's costs decrease. But what counts as "meaningful time" differs significantly. Getting custody from 28% to 30% might unlock a substantial payment reduction in one jurisdiction and do nothing in another.
US States
Typically 20–35% parenting time
Most states trigger a shared custody adjustment when the non-custodial parent has at least 20–35% of overnights. Above that threshold, the Melson or cross-credit formula applies, often significantly reducing the obligation.
United Kingdom
52+ overnights per year
The CMS reduces payments by a fixed percentage for shared care: 1/7 reduction for 52–103 nights, 2/7 for 104–155, 3/7 for 156–174 nights, and 50% for 175+ nights (plus half the basic rate returned).
Australia
Care percentage → cost percentage
Care percentage (nights) is converted to a cost percentage via a non-linear table. At exactly 35% care, the cost contribution recognized jumps significantly. At 50% shared care, payments often offset to near zero.
New Zealand
28% for recognition, 35% for payments
Below 28% care, the non-resident parent has no recognized cost contribution. Between 28–34%, care costs are recognized but payments still flow one way. At 35%+, the formula genuinely cross-credits both parents.
Child support orders are not permanent — here's when to recalculate and file for modification
A child support order is based on a snapshot of circumstances at the time it was issued. Circumstances change. Courts and agencies in every country allow — and sometimes require — modifications when circumstances change substantially.
Grounds for modification
- Substantial income change (typically 15–20%+)
- Change in custody or parenting time
- Job loss or new employment for either parent
- Change in the child's needs (healthcare, education)
- Parent remarries and household income changes
- Child reaches emancipation age
In the US, most states have a "three-year rule" — you can request a review every three years regardless of changed circumstances. Many states also allow review when the resulting amount would change by 10–15% or more from the current order.
Use this calculator to estimate what a new order would look like before spending money on legal fees. If the projected change is modest, it may not be worth the cost of filing. If it's substantial, you have a concrete number to bring to mediation or your attorney.
Tax note
Child support is not tax deductible for the payer and not taxable income for the recipient in the US, Canada, UK, Australia, and New Zealand — unlike spousal support, which has different tax treatment in some countries.
Imputed income: when courts assign the salary you could earn — not what you actually earn
Every country covered by this calculator allows courts to impute income — assigning a parent what they are capable of earning, regardless of what they actually earn. This protects children when a parent voluntarily reduces their income to lower a support obligation or claim higher support.
Canada — Section 19 grounds (2026)
- Intentional under-employment or unemployment
- Income diverted through corporation or trust
- Unreasonably deducted business expenses
- Significant income from dividends or capital gains taxed at lower rates
- Parent exempt from federal or provincial income tax
- Parent lives in a lower-tax country
- Failed to provide income information when required
2026 update: S.A. v. Z.R., 2026 BCCA 19 confirmed the evidentiary burden shifts to the underemployed parent once a prima facie case is established.
🇺🇸 United States
Courts assess capacity based on age, education, work history, skills, health, and local job market availability. A parent who quits a $120K/year job to earn $30K may be assessed at $120K. Voluntary lifestyle choices — becoming a stay-at-home parent after a child is school-age — are treated differently by state.
🇬🇧 🇦🇺 🇳🇿 UK / Australia / NZ
UK CMS uses HMRC gross income data (often from the previous tax year); if income has dropped significantly without explanation, historic income may be used. Australia's Services Australia assesses capacity to earn. New Zealand's IRD can impute income based on work capacity under the Child Support Act 1991, s.44.
Self-employed parents
All jurisdictions scrutinize self-employed parents who show low net income after business deductions. Courts may add back personal expenses run through a business, depreciation, and non-arm's-length transactions to arrive at a truer income figure.
Sources: Canada Federal Child Support Guidelines s.19; S.A. v. Z.R., 2026 BCCA 19; Drygala v. Pauli, 2002 CanLII 41868 (ON CA); OCSE; NZ Child Support Act 1991 s.44.
Child support enforcement in 2026: the tools that reach across state lines — and into criminal law
US child support arrears total over $116 billion (FY2022, HHS OCSE). The federal–state enforcement apparatus collects $26.7 billion/year and deploys tools that range from automatic wage deduction to passport denial to federal felony charges.
Income withholding
71% of all US collections (FY2024)
Mandatory in all new child support orders. Takes effect automatically within 14 days. Has priority over all other wage attachments. Applies to wages, self-employment, unemployment, Social Security Disability, and Workers' Compensation.
Federal/state tax refund intercept
$1.6B collected via federal offsets in FY2021
Threshold: $500 in arrears for non-TANF families; $150 for TANF families. Applied automatically when the arrearage is certified. State tax refunds intercepted under separate state programs.
Passport denial
$2,500+ arrears threshold; ~$621M recovered since program start
Anyone owing $2,500+ in child support arrears is automatically certified to the State Department. Passport applications are denied; existing passports can be revoked. Lifted only after the debt is fully paid or a payment plan is established and current.
License suspension
Driver's · Professional · Recreational licenses
All states suspend or restrict licenses for non-payment. This includes driver's licenses, professional and occupational licenses (nursing, contracting, law, medicine), and recreational licenses (hunting, fishing). Available once arrears exceed state-specific thresholds, typically $500–$2,000.
Federal criminal prosecution
18 U.S.C. §228 — up to 2 years federal prison
The Child Support Recovery Act makes it a federal crime to willfully fail to pay support for a child living in another state: misdemeanor (>$5,000 or >1 year past due) or felony ($10,000+ or >2 years past due). Felony conviction can result in up to 2 years imprisonment plus restitution of full arrears.
Other enforcement tools
Asset seizure · Insurance · Lottery intercept
Seizure of bank accounts and retirement funds; liens against property; interception of lottery winnings and insurance settlements; credit bureau reporting (damages credit scores immediately). Contempt of court proceedings available at the state level.
Sources: HHS OCSE Annual Report FY2024; Congress.gov CRS RS22380; 18 U.S.C. §228; Tollestrup 2026 CSE Testimony (Ways & Means Committee, Jan 2026).
High-income child support in 2026: when the guidelines run out and courts decide
Every guideline formula has an income cap. Above that cap, courts use discretion — considering the child's actual needs, the family's pre-separation standard of living, and the ability to pay. Several states updated their caps in 2025–2026:
| State / Country | Guideline cap (2026) | Above-cap standard | 2026 change |
|---|---|---|---|
| Washington | $50,000/mo combined net | Court discretion; child's needs + standard of living | Expanded from lower cap — Jan 2026 ✓ |
| Colorado | $40,000/mo combined gross ($480,000/yr) | Extrapolation + deviation from guidelines allowed | Raised from $30,000/mo — 2026 ✓ |
| Pennsylvania | $30,000/mo combined net | Codified formula above cap (Pa.R.C.P. 1910.16-3.1) — unique | Updated amounts — Jan 2026 ✓ |
| Texas | $11,700/mo net resources | Proven needs of the child only; no formula extension | Cap raised — Sep 2025 ✓ |
| New York | $193,000 combined income | 10-factor Cassano analysis; no presumption either way | Prior CSSA increase — Mar 2024 |
| Canada (Federal) | $150,000 annual income | Section 4: table + ~1.0–1.2%/child on excess income | Ongoing threshold; courts apply discretion above |
What courts consider above the cap
- Child's proven needs — not just basic expenses
- Pre-separation standard of living (vacations, activities, private school)
- Number and ages of children
- Each parent's actual income and assets
- Whether amounts would exceed child's reasonable needs
Pennsylvania: the only state with a codified above-cap formula
Under Pa.R.C.P. 1910.16-3.1 (updated January 2026), when combined monthly net income exceeds $30,000, Pennsylvania applies a specific formula rather than pure judicial discretion. The formula adds a fixed percentage on income above the cap — one of the few jurisdictions globally to extend the guideline math rather than leave high-income cases entirely to judicial judgment.
Sources: divorce.law 2026; lawinterpretation.com; pricefamlaw.com (CO cap 2026); Canada Federal Child Support Guidelines s.4; github.com/unvow/child-support-guidelines-by-state.
The monthly and annual support amounts shown above come from your selected country, state or province, both parents' incomes, number of children, custody percentage, and optional adjustments — calculated instantly in your browser, not from a court or government agency feed. For US states we route to either the Income Shares model (most states) or the Percentage of Income model (Texas, Wisconsin, and a few others). Canada, UK, Australia, and New Zealand use their own published formulas. Below are the exact steps, model differences, and worked examples you can verify against the calculator.
Core formulas
| Metric | Formula |
|---|---|
| Combined monthly income (US) | Parent A gross + Parent B gross |
| Income share (US) | Parent income ÷ Combined income × 100 |
| Basic obligation (Income Shares) | State schedule amount from combined income + number of children |
| Custody adjustment (Income Shares) | Reduce obligation when paying parent has 30%+ parenting time |
| Monthly support (Income Shares) | Payer's income share of obligation minus custody credit |
| Monthly support (Percentage of Income) | Paying parent's income × state percentage (by child count) |
| Health insurance add-on | 50% of monthly child health insurance cost (split) |
| Childcare / medical add-ons | Split proportionally by each parent's income share |
| Other dependents credit | −5% of base support per additional dependent |
| Annual support | Monthly support × 12 |
Order of operations
Route by country
US → state model · CA → federal guidelines · UK → CMS · AU → Services Australia · NZ → IRDcalculateChildSupport() dispatches to the appropriate national formula based on the country you select.
Select US calculation model
getStateCalculationModel(state) → income-shares OR percentage-of-incomeMost US states use Income Shares. Alaska, Mississippi, Nevada, North Dakota, Texas, and Wisconsin use Percentage of Income (with state-specific rates and tables).
Calculate base support
Income Shares: combined income schedule · Percentage: paying parent income × rateIncome Shares finds a basic child-support obligation from combined parental income, then assigns each parent's proportional share. Percentage states apply a flat or tiered rate to the paying parent's income only.
Apply custody / parenting time
Reduction when paying parent has ≥30% custody (Income Shares states)When the paying parent has significant parenting time, support is reduced — up to 50% at 100% custody in our simplified model. State-specific parenting-time credits may also apply.
Apply optional adjustments
Base + health insurance + childcare + medical − dependents − existing supportHealth insurance, childcare, and extraordinary medical costs are added and split by income share. Other dependents and existing support obligations reduce the final amount.
Apply state minimum and caps
max(monthlySupport, state minimum) · income caps may trigger court discretionEach state has guideline income floors and caps. Amounts above the cap are estimates only — courts often deviate for high-income parents.
Models by country
| Country | Model |
|---|---|
| United States | Income Shares (41 states) or Percentage of Income (6 states) |
| Canada | Federal Child Support Guidelines (table lookup) |
| United Kingdom | CMS 6-step formula |
| Australia | 8-step formula assessment |
| New Zealand | IRD formula assessment |
Worked example 1 — California — Income Shares (calculator defaults)
Verify: Combined $8,000.00 → Parent A 62.5% / Parent B 37.5% → $130.50/mo
| Field | Value |
|---|---|
| State | California |
| Calculation model | income-shares |
| Parent A gross income | $5,000.00 |
| Parent B gross income | $3,000.00 |
| Combined income | $8,000.00 |
| Parent A income share | 62.5% |
| Parent B income share | 37.5% |
| Children | 1 |
| Parent A custody | 70% |
| Paying parent | Parent B |
| Monthly support | $130.50 |
| Annual support | $1,566.00 |
| % of payer income | 4.35% |
Worked example 2 — Texas — Percentage of Income (same incomes)
Verify: $3,000.00 × 20% = $600.00/mo (approx.; TX uses net resources in practice)
| Field | Value |
|---|---|
| State | Texas |
| Calculation model | percentage-of-income |
| Paying parent income | $3,000.00 |
| Children | 1 |
| TX rate (1 child) | 20% |
| Monthly support | $600.00 |
| Annual support | $7,200.00 |
| % of payer income | 20% |
Constants used
| Item | Value |
|---|---|
| Default state | California (CA) |
| Default children | 1 |
| Default Parent A income | $5,000/mo |
| Default Parent B income | $3,000/mo |
| Default custody (Parent A) | 70% |
| Default paying parent | Parent B |
| Percentage-of-income states | AK, MS, NV, ND, TX, WI |
| TX rate (1 child, standard) | 20% of paying parent income |
| Confidence range | ±10–15% of estimate |
Official sources
Frequently Asked Questions
Official Sources by Country
🇬🇧 United Kingdom
🇦🇺 Australia
🇳🇿 New Zealand
Legal Disclaimer: This calculator provides estimates for planning purposes only and is not legal advice. Courts and government agencies make final determinations regarding child support. Guidelines are updated regularly and may change. Always consult a family law professional for advice specific to your situation.
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