Term Deposit Calculator NZ: Interest After Tax
Estimate how much interest a New Zealand term deposit could earn before and after tax. Enter your deposit, term, annual interest rate, payment frequency and either an RWT or PIR rate to see your estimated earnings and final value.
Updated 4 July 2026 · Rate guide uses the latest Reserve Bank monthly averages available on this date
- The calculator shows gross interest, estimated tax, after-tax interest and your final value.
- Use RWT for a standard term deposit. Use PIR only when the product is a qualifying PIE or Term PIE investment.
- Quick-pick rates are market averages, not offers. Always enter the actual rate and payment terms supplied by your provider.
How to calculate term deposit interest in New Zealand
Interest paid at maturity:Gross interest = Deposit × annual rate × (term in months ÷ 12)
Interest reinvested during the term:Final value = Deposit × (1 + annual rate ÷ payment periods)^(payment periods × years)
After-tax value:Deposit + interest remaining after the selected RWT or PIR rate is applied
Actual banks may calculate daily interest, use special stub-period rules or pay interest to another account instead of reinvesting it. This tool provides an estimate only.
Your term deposit details
Your term deposit estimate
RWT estimateCalculating your estimate…
Comparison of estimated gross interest and interest remaining after the selected tax treatment.
| Initial deposit | $0.00 |
| Gross interest before tax | $0.00 |
| Estimated RWT deducted | $0.00 |
| Interest after tax | $0.00 |
| Estimated final value after tax | $0.00 |
| Effective annual return after selected tax | 0.00% |
How this Term Deposit Calculator NZ works
For interest paid at maturity, the calculator uses simple interest: the deposit is multiplied by the annual rate and the fraction of a year represented by the term. For monthly, quarterly, half-yearly or annual reinvestment, it compounds the return at the selected frequency.
When RWT or PIR is selected, tax is applied to the interest. For reinvested interest, the estimate assumes tax is deducted as each interest payment is credited and only the net interest remains available to compound.
- RWT is the usual tax treatment for interest on a standard New Zealand term deposit.
- PIR applies only to a qualifying Portfolio Investment Entity product, such as a Term PIE.
- Gross only is useful for comparing advertised returns but is not an after-tax estimate.
- Actual results can differ because providers may calculate interest daily, use different payment dates or round each payment.
Current NZ term deposit rate guide
The latest Reserve Bank data available on 4 July 2026 reports the following average advertised rates for new bank term deposits of at least $10,000. The data covers May 2026 and was released on 8 June 2026. These are market averages, not guaranteed offers.
| Term | Average rate | Calculator quick pick |
|---|---|---|
| 1 month | 1.89% p.a. | No |
| 3 months | 3.00% p.a. | Yes |
| 6 months | 3.56% p.a. | Yes |
| 9 months | 3.61% p.a. | Yes |
| 1 year | 3.82% p.a. | Yes |
| 18 months | 3.95% p.a. | Yes |
| 2 years | 4.16% p.a. | Yes |
Source: Reserve Bank of New Zealand, B26 term deposit interest-rate series.
RWT vs PIR on term deposits
Resident Withholding Tax (RWT) is deducted from interest earned on standard New Zealand bank deposits. For most individuals who have supplied an IRD number, the available rates are 10.5%, 17.5%, 30%, 33% and 39%. Your selected rate should normally match your income tax rate. If you do not choose a rate, interest is generally deducted at 33%.
Prescribed Investor Rate (PIR) applies to income from a multi-rate PIE. For New Zealand resident individuals, the usual PIR options are 10.5%, 17.5% and 28%. Selecting PIR in this calculator does not turn a standard term deposit into a PIE product; the underlying investment must actually be structured as a Term PIE or another qualifying PIE.
Choosing the right tax rate depends on your income history, entity type and personal circumstances. Use Inland Revenue's official guidance or speak with a tax professional when unsure.
Things to know before opening a term deposit
- Rates and minimum deposits vary. Compare the actual rate, minimum investment, payment frequency and term conditions before committing money.
- Early withdrawal can reduce your return. A provider may require notice, reduce the interest rate or refuse an early withdrawal except in hardship circumstances.
- Check whether interest is reinvested. Interest paid into another account does not compound inside the deposit.
- DCS protection is capped. Eligible deposits are covered up to $100,000 per depositor, per licensed deposit taker, when held in DCS-protected accounts.
- PIE products are different investments. Confirm whether a Term PIE is a protected deposit and review the provider's product disclosure and DCS information.
How to use the Term Deposit Calculator NZ
- Enter your deposit. Add the amount you plan to invest.
- Choose the term. Enter the number of months or use a current market-average quick pick.
- Enter the quoted rate. Use the annual rate supplied by the bank or deposit taker.
- Select how interest is credited. Choose at maturity or a reinvested payment frequency.
- Choose the tax treatment. Select gross only, RWT or PIR and then select the relevant tax rate.
- Review the result. Compare gross interest, tax, after-tax earnings, final value and the DCS coverage reminder.
Term Deposit Calculator NZ Frequently Asked Questions
Multiply the deposit by the annual interest rate and adjust it for the term length. When interest is reinvested during the term, each credited payment can also earn interest, so a compound-interest calculation is used.
Yes. It always shows gross interest. You can then select RWT or PIR to estimate tax deducted, after-tax interest and final value, or select gross only for a before-tax comparison.
Resident Withholding Tax is tax deducted from interest earned on a standard New Zealand deposit. The correct rate generally depends on your taxable income and should be provided to the bank or deposit taker.
Prescribed Investor Rate is the tax rate applied to income from a qualifying multi-rate Portfolio Investment Entity. The standard individual PIR options are 10.5%, 17.5% and 28%.
Not automatically. A Term PIE may produce a different after-tax result for some investors, but the correct PIR and suitability of the product depend on your income history, tax position, product terms and circumstances.
No. Monthly interest may be paid into another account rather than added back to the deposit. Select monthly reinvestment only when the product allows the interest to remain invested and earn further interest.
No. They are Reserve Bank market averages for selected terms from the latest monthly data available when this page was reviewed. Enter the current rate offered by your chosen provider before relying on the estimate.
Eligible term deposits held in DCS-protected accounts are covered up to $100,000 per depositor, per licensed deposit taker. Check the provider and product because not every financial product is covered.
That depends on the provider's terms. Early withdrawal may require notice, be limited to hardship situations or result in a reduced interest payment, so check the conditions before investing.
No. It provides a general estimate using the values entered. It does not determine your correct tax rate, assess a provider's risk or consider your complete financial circumstances.
This calculator is a high-level illustration only. Actual interest, payment timing, tax deductions, fees, early-withdrawal adjustments and DCS coverage can differ by provider and product. The quick-pick rates are market averages, not recommendations or guaranteed offers. This is not financial or tax advice.