NZ Child Support Calculator 2026
Estimate child support using the IRD formula assessment — (i% − c%) × p — based on both parents' income after the living allowance ($29,909), care percentage, and child expenditure tables.
By Sammy S. · Founder · AuthorUpdated for 2026
Estimates only — not legal advice. IRD makes final determinations. Consult a family law lawyer.
Child Support Calculator
Enter details to estimate payments
IRD formula based on both parents' income, care %, and child expenditure tables.
Parent A's custody %. Parent B calculated automatically.
New Zealand · IRD Formula
Estimated Child Support
Weekly
$63
Biweekly
$126
Monthly
$273
Annual
$3,270
Income & custody split
Calculation breakdown
Guideline: Child Support Act 1991
Updated: 2025-2026 · Official source
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 values — 2025–2026
- Living allowance$29,909Deducted from each parent's income first
- Supported living allowance$33,523
- Minimum annual rate$1,175/yr
- Minimum care to receive payments35% (≈128 nights/yr)
- Care recognised at all28%+ (≈103 nights/yr)
The IRD formula
Positive result = you pay. Negative result = you receive (if 35%+ care).
Other countries
Related tools
The IRD formula — elegant in theory, nuanced in practice
New Zealand's child support formula is conceptually elegant: (i% − c%) × p. Your income percentage minus your care cost percentage, multiplied by what research says children cost. If you earn more than your share of the child's time, you pay. If you care for the child more than your income would suggest, you receive. Both parents contribute according to their financial capacity and time investment.
The living allowance ($29,909 for 2025–2026) is deducted from both parents' taxable income before the formula runs. This recognises that each parent needs a base level of income to maintain themselves. For parents with low incomes, this allowance can mean their child support income is zero, which limits their contribution.
The 28% and 35% care thresholds — the most important numbers in NZ child support
New Zealand has two distinct care thresholds, and the difference between them matters enormously. The 28% threshold (approximately 103 nights/year) is the point at which care is "recognised" in the formula — the parent's care cost percentage is greater than zero. Below 28%, the formula treats you as if you have no care at all, resulting in maximum liability.
The 35% threshold (approximately 128 nights/year, or 5 nights per fortnight) is the point at which a parent can actually receive child support. This creates an unusual scenario: a parent with 30% care has recognised care that reduces the payer's liability, but the lower-income parent with 30% care cannot receive payments because they don't meet the 35% threshold.
Child Expenditure Tables 2025–2026 — what “p” actually equals
Effective 1 April 2025 – 31 March 2026. New values take effect 1 April 2026. Source: Official IRD PDF.
The “p” in the formula is the annual child expenditure amount from IRD's tables. These represent what New Zealand research estimates parents spend on children at different combined income levels. The income ranges are based on Average Weekly Earnings (AWE) for the June quarter — the per-child rate decreases as income rises (diminishing marginal expenditure), and teenagers are more expensive than younger children.
Children aged 12 and under — combined child support income
| Combined income range | 1 child | 2 children | 3+ children |
|---|---|---|---|
| $0 – $41,244 | 17¢ per $1 | 24¢ per $1 | 27¢ per $1 |
| $41,245 – $82,489 | $7,011 + 15¢ | $9,899 + 23¢ | $11,136 + 26¢ |
| $82,490 – $123,733 | $13,198 + 12¢ | $19,385 + 20¢ | $21,860 + 25¢ |
| $123,734 – $164,977 | $18,147 + 10¢ | $27,634 + 18¢ | $32,171 + 24¢ |
| $164,978 – $206,222 | $22,271 + 7¢ | $35,058 + 10¢ | $42,070 + 18¢ |
| $206,223+ | $25,158 cap | $39,182 cap | $49,494 cap |
Children aged 13 and over — combined child support income
| Combined income range | 1 child | 2 children | 3+ children |
|---|---|---|---|
| $0 – $41,244 | 23¢ per $1 | 29¢ per $1 | 32¢ per $1 |
| $41,245 – $82,489 | $9,486 + 22¢ | $11,961 + 28¢ | $13,198 + 31¢ |
| $82,490 – $123,733 | $18,560 + 12¢ | $23,510 + 25¢ | $25,984 + 30¢ |
| $123,734 – $164,977 | $23,509 + 10¢ | $33,821 + 20¢ | $38,357 + 29¢ |
| $164,978 – $206,222 | $27,633 + 9¢ | $42,070 + 13¢ | $50,318 + 20¢ |
| $206,223+ | $31,345 cap | $47,432 cap | $58,567 cap |
From 1 April 2026: New income brackets apply (AWE $1,652.72/wk → $0–$42,971 / $42,972–$85,941 / … / $214,855+), with updated base amounts and caps. Living allowance rises to NZ$30,557; minimum annual rate to NZ$1,211. See 2026-2027 tables on IRD.