PIR Overpayment Recovery Calculator

A prescribed investor rate is easy to set once and never look at again, which is exactly why so many of them are wrong. The most common case is a KiwiSaver account opened at a student or first-job income, sitting on 10.5% a decade later while the member earns enough for 28%. The reverse is just as common, since people often assume the PIR matches their income tax rate and select 28% when they are entitled to 17.5%. Either way the error compounds quietly, because nothing on a payslip or a bank statement ever flags it. This page quantifies the damage. Enter the PIE income from your annual tax certificates for the last five tax years, the rate that was applied and the rate that should have been, and it returns the tax paid, the tax that was due, the difference year by year, and the direction of the error. It also separates the two halves of the loss that people conflate: the tax itself, which Inland Revenue's end-of-year calculation does return as a refundable credit where you overpaid, and the investment growth on that money, which is gone permanently because the tax was deducted from your fund and never earned anything. The second figure is the argument for fixing the rate today rather than only chasing the history.

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Nothing Tells You The Rate Is Wrong

A wrong PAYE code shows up in a payslip. A wrong PIR shows up nowhere. The tax is deducted inside the fund before the return reaches your balance, so the only place it appears is the annual tax certificate, which most people never open.

That is why the errors run for years. The rate was correct when it was set, income changed, and nothing in the system prompted a review.

Worked Example: Five Years At 28% Instead Of 17.5%

PIE income of $2,400.00, $2,900.00, $3,500.00, $4,200.00 and $5,000.00 across the five tax years to 31 March 2026, totalling $18,000.00.

At the 28% rate that was applied, the tax was $5,040.00. At the correct 17.5%, it should have been $3,150.00. The difference is $1,890.00.

Under Inland Revenue's end-of-year PIE calculation that overpayment is a PIE credit. It reduces any income tax payable and any remaining credit is refunded, so the $1,890.00 is recoverable.

The growth is not. Because the tax was taken out of the fund, it never earned anything. At 5.00% the $1,890.00 would have been $2,052.02 by the end of the most recent year, so $162.02 is permanently gone even after a full refund.

The Error Runs Both Ways

The version that costs you money is the rate that was too high. The version that surprises people is the rate that was too low.

Inland Revenue's position on an underpayment is that it becomes a PIE debt added to the income tax you have to pay. Someone who left 10.5% running while their income supported 28% owes the 17.5 percentage point difference on every dollar of attributed PIE income. On the same $18,000.00 that is $3,150.00 payable, not receivable.

This is worth knowing before you go looking. Checking an old KiwiSaver PIR can produce a bill rather than a refund, and either way you are better off knowing.

Why KiwiSaver Is Where It Hides

KiwiSaver accounts are frequently opened at the start of a working life, at a student or first-job income, and a 10.5% rate is genuinely correct at the time. Fifteen years later the income is different and the rate is not.

Employer-arranged sign-ups are the other source, because a rate often gets applied without the member choosing one at all.

The compounding effect is what makes KiwiSaver the expensive case. It is usually the largest PIE balance a person holds and the one held longest, so the attributed income is largest exactly where the rate is most likely to be stale. Our KiwiSaver calculator shows what a difference in the net return does across a working life.

The PIR Test Is Not Your Tax Rate

There are three prescribed investor rates, 10.5%, 17.5% and 28%, and the top one is a cap. Income tax rates go to 39%.

The test looks at the last two income years and takes the more favourable result. You qualify for 10.5% if in either year your taxable income was $15,600 or less and your taxable income plus PIE income was $53,500 or less. You qualify for 17.5% if your taxable income was $53,500 or less and the combined figure was $78,100 or less. Otherwise it is 28%.

The detail that catches people is that PIE income counts in the test, so a strong year in a large KiwiSaver balance can push you into a higher band on its own. Our PIR rate calculator runs the test properly.

Fix It Once, With Every Provider

The rate is set per provider, not centrally. If you hold a KiwiSaver account, a managed fund and a PIE savings account, all three need updating, and changing one does nothing to the others.

It is usually a single field in the provider's app or online account. Inland Revenue does notify providers where it thinks a rate is wrong, but treat that as a backstop rather than the mechanism.

Once the rate is right, the wrapper does what it is supposed to. Our PIE savings vs bank savings calculator shows what a correct PIR is worth against an ordinary account taxed at your marginal rate.

Related NZ PIE and Tax Calculators

• PIE PIR Rate Calculator: work out the rate that should apply to you.
• PIE Savings vs Bank Savings Calculator: what a correct PIR is worth.
• KiwiSaver Calculator: what a change in net return does over a working life.
• Marginal Tax Rate Calculator: the rate that applies to your next dollar of income.
• RWT on Interest Calculator: tax on interest outside a PIE.