Child Support Across Six Jurisdictions
Child support exists so a child's standard of living does not collapse because their parents separated. Every serious jurisdiction has a mechanism for it, but they differ sharply in how they calculate it. This guide explains the principles and the actual approaches in South Africa, the United Kingdom, the United States, Australia, Canada and New Zealand. It is educational guidance, not legal advice — figures change, and only a professional in your jurisdiction can apply the rules to your facts.
Two families of system. Some jurisdictions use a formula (a statutory table or percentage applied to income); others use discretion (a court weighs the child's needs against each parent's means). Most modern systems are hybrids: a starting formula, adjusted for shared care and special costs.
South Africa — discretion under the Maintenance Act
South Africa does not use a fixed formula. Maintenance claims (for children and, where applicable, a spouse) are decided under the Maintenance Act 99 of 1998, with courts applying a needs-and-means test.
- The test: the child's reasonable needs, weighed against each parent's income, assets and standard of living — and each parent's duty to contribute in proportion to their means.
- No automatic percentage: there is no statutory slice of income. Two cases with identical incomes can produce different orders because needs and circumstances differ.
- Practical effect: a well-documented budget of the child's actual costs — school, medical, housing, food, care — is the strongest evidence you can bring.
- Enforcement: maintenance orders are enforced through the maintenance court, with remedies including garnishing wages.
Because there is no table, the app's calculator can only estimate. Treat any South African figure as a starting point for negotiation, not a legal entitlement.
United Kingdom — the Child Maintenance Service formula
In England, Wales, Scotland and Northern Ireland, the Child Support Act 1991 (as amended) creates a statutory scheme administered by the Child Maintenance Service (CMS). The CMS applies a formula to the paying parent's gross income.
- Basic rate: for most cases, a percentage of gross weekly income — 12% for one child, 16% for two, 19% for three or more — with reductions where the paying parent also supports other children.
- Reduced rate and flat rate: lower-income payers fall into a reduced-rate band or a flat rate (a nominal weekly amount), rather than the basic-rate percentages.
- Shared care: overnight stays with the paying parent reduce the amount in bands.
- Income above the cap: beyond a statutory earnings ceiling the CMS does not assess, and the matter can go to court for a top-up.
The percentages above are the well-established CMS bands; always confirm current rates with the CMS or an adviser, as figures are revised.
United States — state law, income-shares in most states
There is no single national formula. Child support is state law, and each state has its own guidelines. The dominant model is the income-shares model: the two parents' combined incomes are used to estimate what they would have spent on the child together, and each parent contributes their proportional share.
- Income shares: most states; the non-custodial parent pays a share based on relative income.
- Percentage-of-income: a minority of states apply a flat or tiered percentage of the non-custodial parent's income.
- Adjustments: parenting time, health insurance, childcare and other children all modify the base amount.
- Enforcement: state agencies garnish wages and intercept tax refunds.
Because guidelines are state-specific and detailed, the app's calculator is an approximation only — your state's official calculator or an attorney is the authoritative source.
Australia — Services Australia income-shares assessment
Australia administers child support through Services Australia under the Child Support (Assessment) Act 1989. The formula is an income-shares model built on both parents' taxable incomes and their care percentages.
- Both parents assessed: each parent's income and each parent's care percentage feed the same formula.
- Cost of children: statutory cost-of-children tables scale the total support obligation to combined income.
- Self-support amount: each parent's income is reduced by a self-support threshold before the child cost is shared.
- Care adjustment: the amount shifts with the number of nights of care each parent provides.
Services Australia's own estimator is the authoritative calculator; the app approximates the structure but not the precise annual tables.
Canada — Federal Child Support Guidelines tables
Canada uses the Federal Child Support Guidelines under the Divorce Act. The system is table-based: the paying parent's gross income and the number of children map to a monthly amount, with each province having its own table (tables differ by province tax rates).
- Table amount: a fixed monthly figure read from the guideline table for the payer's income and child count.
- Add-ons: special or extraordinary expenses (childcare, medical, education) are usually shared in proportion to income, on top of the table amount.
- Shared custody: where parenting time is near-equal, the set-off approach compares what each parent would pay and nets the difference.
- Undue hardship: a payer can seek a variation where the table amount causes genuine hardship.
New Zealand — income-based formula under the Child Support Act
New Zealand's Child Support Act 1991 applies a formula to the paying parent's income. The headline rates are a percentage of income — commonly 18% for one child, 24% for two, and 29% for three or more — with the exact assessment depending on income thresholds and care arrangements.
- Income-based: the percentage applies to income above a living-allowance threshold, so low-income payers are protected.
- Shared care: the formula adjusts for the care the paying parent provides.
- Administration: Inland Revenue administers assessment and collection.
Rates and thresholds are revised; confirm current figures with Inland Revenue or an adviser.
Practical principles that hold everywhere
- Apply formally. An informal arrangement that stops is hard to enforce; a formal assessment or order is not.
- Keep records. Every payment, dated and documented, protects both parents from dispute.
- Reassess on change. A change of income, care arrangement or the child's needs usually justifies a reassessment — don't let an outdated amount quietly become the new normal.
- Separate the money from the conflict. Child support is about the child's costs, not a scorecard between parents. Keep the two apart.
Educational information only — not legal or financial advice. Statutory rates and tables change, and jurisdiction rules vary by state, province and territory. Confirm current law and your entitlements with a qualified professional.
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