NZ Budget 2026 Net Impact Calculator

Five changes are modelled, each compared to its 2025-26 baseline — everything that moves a household's cash between 2025-26 and 2026-27. They are grouped here because they all land on 1 April 2026, not because one Budget decided them all: two were settled by Budget 2025, one by an Order in Council six months before Budget 2026, and one — the IWTC boost — by a stand-alone announcement on 24 March 2026, enacted eight weeks before the Budget. Only the donation cap was actually decided at Budget 2026. Attribution is noted per line.

1. In-Work Tax Credit boost — base rises from $97.50 to $147.50/week for 2026-27 only. Applies to families with dependent children where at least one parent meets the work-hours threshold and isn't receiving a main benefit. Not a Budget 2026 measure — announced 24 March 2026 and enacted 30 March 2026 (eight weeks before the Budget) via an Amendment Paper to the Taxation (Annual Rates for 2025-26, Compliance Simplification, and Remedial Measures) Act 2026. Its cost was charged against the Budget 2026 operating allowance, which is the only sense in which it is a Budget item.
2. Family Tax Credit + Best Start CPI uplift — FTC eldest $144.69 → $152.33/wk; FTC subsequent $117.88 → $124.12/wk; Best Start $73.81 → $77.71/wk. Best Start year-1 becomes income-tested at $79,000 / 21% for babies born on or after 1 April 2026. Not a Budget 2026 measure — statutory CPI indexation set by the Income Tax (Tax Credit) Order 2025 (SL 2025/260), made by Order in Council on 17 November 2025 under s MF 7 of the Income Tax Act 2007, six months before the Budget.
3. WfF abatement settings — threshold $42,700 → $44,900 (helps), rate 27% → 27.5% (hurts slightly). Net effect is positive for most families above the threshold. Budget 2025 — s 7 of the Taxation (Budget Measures) Act 2025 (2025 No 26), commencing 1 April 2026. Budget 2026 confirmed the date, it did not set the settings.
4. KiwiSaver employer match — 3% → 3.5% from 1 April 2026, net of Employer Superannuation Contribution Tax (ESCT) at your applicable bracket. Budget 2025 — s 22(1) of the same Act. Budget 2026's action here was to defer the further step to 4%, keeping 2026-27 at 3.5%.
5. Donation tax credit $100k cap — only impacts donors above $100,000/year of eligible donations. Below that, the credit is unchanged at 33⅓%. Budget 2026 — s 6 of the Taxation (Budget Measures) Act 2026 (2026 No 25), applying to gifts made on or after 1 April 2027, so it is shown separately and does not move your 2026-27 total.

The calculator does NOT quantify PAYE bracket freeze / fiscal drag — there's no Budget 2026 action there, just inaction that lets bracket creep continue. See the PAYE freeze + fiscal drag insight for that analysis.