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Term Deposit Calculator

Calculate maturity value, gross interest, and after-tax effective rate on NZ term deposits. Supports monthly/quarterly/annual/at-maturity compounding.

By Konstantin IakovlevPublished 28 March 2026Last reviewed
Data stays on your deviceRBNZ market data

About this calculator

This calculator implements RBNZ wholesale rate data + IRD RWT rules from RBNZ + IRD (RWT). Last consulted 18 May 2026. Verify the figures yourself by following the link.

Current NZ term deposit rates (mid-2026)

Indicative — varies by bank, term, amount
  • 3-month rate: ~4.40–4.80%
  • 6-month rate: ~4.85–5.20%
  • 12-month rate: ~5.10–5.50%
  • 2-year rate: ~5.00–5.30%
  • RWT applies on interest: 10.5%-39% (your marginal)
  • No IRD number: 45% default

Source: RBNZ — Interest rates

Disclaimer

This calculator provides estimates for general information purposes only. Results should not be relied upon as professional financial, tax, or legal advice. Tax rates and thresholds are based on publicly available IRD data and may change. Always consult a qualified tax agent or financial adviser for advice specific to your circumstances.

How NZ term deposit returns are calculated

Compound interest formula adjusted for NZ RWT on interest earned.

  1. 1

    Compound interest formula

    Final = P × (1 + r ÷ n)^(n×t)

    P = principal, r = annual rate, n = compounding periods/yr, t = years.

  2. 2

    Gross interest earned

    Gross_interest = Final − P

    The taxable interest amount.

  3. 3

    RWT deduction

    RWT = Gross_interest × your_RWT_rate

    Bank deducts RWT at source. 10.5%, 17.5%, 30%, 33%, 39%, or 45% if no IRD#.

  4. 4

    After-tax effective rate

    Effective_rate = ((P + Net_interest) ÷ P)^(1÷t) − 1

    Annualised return after tax.

Worked example

Inputs: $10,000 at 5.20% p.a., 12 months, monthly compounding, 30% RWT

Result: Final $10,532. Gross interest $532. RWT $160. Net $372. Effective 3.72% after tax.

Frequently Asked Questions

How is RWT taxed on a NZ term deposit?
Resident Withholding Tax (RWT) is deducted by your bank on interest earned. The rate matches your marginal income tax bracket: 10.5%, 17.5%, 30%, 33%, or 39%. If you don't supply an IRD number, the bank deducts 45% by default. RWT is credited against your year-end tax. Source: IRD — RWT.
Is compounding allowed on NZ term deposits?
Most banks pay interest at maturity for shorter terms (3-12 months) and offer compounding (monthly, quarterly, or annually) on longer terms. Compounding gives a higher effective annual rate. For maximum returns, choose monthly compounding on long-term (24-60 month) TDs. Source: RBNZ + bank product disclosures.
What are the break fees on a NZ term deposit?
All major NZ banks charge break fees if you withdraw a TD early. Typical structures: (1) Reduction in interest rate — bank pays interest at a lower 'on-call' rate (~0.05-1%) instead of the agreed TD rate for the broken period, plus (2) an admin fee of $25-50. Some banks (ASB, Kiwibank) require 31 days' notice for early withdrawal. Hardship exceptions may waive the fee. Strategy to avoid break fees: 'laddering' — split your $50k across 3, 6, 9, 12 month TDs so something matures every 3 months. This gives you regular liquidity while still earning long-term rates. Source: bank product disclosure statements + RBNZ.
Should I split my term deposit across multiple banks?
Yes, if your total deposits exceed $100,000. From 1 July 2025, NZ has a Depositor Compensation Scheme (DCS) that protects deposits up to $100,000 per depositor per institution if the bank fails. Splitting $300,000 across 3 banks gives you $300,000 of protection vs only $100,000 in one bank. Eligible institutions: registered banks (ANZ, ASB, BNZ, Kiwibank, Westpac, TSB, Heartland, SBS, Co-operative Bank). Note: building societies and finance companies have different rules. Joint accounts count as one $100k limit shared between holders. Source: RBNZ Depositor Compensation Scheme.

How this calculator works

This term deposit calculator uses the latest data from official New Zealand government sources to provide accurate results. All calculations are performed in your browser — your data never leaves your device.

All calculations are performed in your browser — your data never leaves your device. Results are for general guidance only and should not be considered professional financial advice.

Built and maintained by Konstantin Iakovlev. Data sourced from the IRD and official New Zealand government sources.

Last reviewed: