Emergency Fund Placement Calculator

Most advice about emergency funds stops at how large one should be, which leaves the more consequential question untouched. A fund of the right size sitting in the wrong place earns nothing, and in New Zealand the placement decision is worth more than most people assume, because the options are taxed three different ways. Interest from a bank account is taxed at your marginal rate. Income inside a portfolio investment entity is taxed at your prescribed investor rate, capped at 28 percent. Money offsetting a mortgage is not taxed at all, because it reduces interest you are charged rather than producing income you are paid, and that single structural difference usually settles the question before the rates are even compared. This page ranks six realistic placements on after-tax return while keeping access in view, because return alone will always point at a term deposit, and a term deposit is not an emergency fund. It separates the placements you can genuinely reach from the ones you cannot, prices the gap between where your money is now and where it should be, and shows how the answer shifts across marginal tax rates. Put your own advertised rates in before acting on it, because the ranking can change and the defaults are illustrative only.

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Three Tax Treatments, Not One

The reason the placements cannot be compared on advertised rates is that they are taxed three different ways.

Bank interest is taxed at your marginal rate through resident withholding tax. At 33%, a third of it is gone before you see it.

PIE income is taxed at your prescribed investor rate, capped at 28%. Identical investment, lower rate, purely because of the wrapper.

Offsetting a mortgage is not taxed at all, because there is no income. You are reducing what you are charged, and a dollar of interest not charged is worth a full dollar.

Worked Example: $25,000 At A 33% Marginal Rate

A transaction account paying nothing returns $0.00.

On-call bank savings at 2.50% earns $625.00 before tax and $418.75 after it, an effective 1.68%.

A PIE cash fund at the same 2.50%, taxed at a 28% PIR, nets $450.00, an effective 1.80%. Same rate, $31.25 more, entirely from the PIR cap.

A mortgage offset at 5.85% is worth $1,462.50, because none of it is taxed. That is more than three times the best taxed alternative you can reach.

The Term Deposit Trap

A 6-month term deposit at 4.00% nets $670.00 after tax, comfortably ahead of both savings options. It is still the wrong home for emergency money.

An emergency fund exists to be available on the day something goes wrong. A placement that requires breaking a term, on arrangements that vary by bank and can materially reduce the interest earned, is not available in the sense that matters.

The $220.00 a year it appears to gain over a PIE cash fund is not payment for a real advantage. It is payment for accepting a constraint that defeats the purpose of the money.

Term deposits are a good product for money with a known date attached. Our term deposit savings calculator covers that case, our term deposit break cost calculator prices what breaking one actually costs, and our term deposit vs PIE fund calculator compares the two on tax.

If You Have A Mortgage, The Question Is Usually Settled

An offset or revolving credit facility is both the highest-returning and the most accessible option on the list, which almost never happens in personal finance.

The advantage also grows with your tax rate, because the offset return is untaxed while every alternative is not. At a 17.5% marginal rate the offset beats the best taxed option by $637.50 a year. At 39% it is $852.50.

Two things to check before moving. A revolving credit facility only works as an emergency fund if it stays undrawn, since a drawn facility is debt rather than a buffer. And some facilities carry a monthly fee, which on a small balance can take back a meaningful share of the gain.

Our mortgage offset calculator covers what offsetting does to the loan itself, which is a larger effect than the annual figure here suggests.

Without A Mortgage, It Comes Down To The PIR Cap

With the offset off the table, the best accessible placement on the worked example is a PIE cash fund at $450.00, ahead of on-call savings at $418.75.

That gap is entirely a tax artefact. Both pay 2.50%; one is taxed at 28% and the other at 33%. If your marginal rate is 28% or below, the two are identical and you should choose on fees, access and the headline rate instead.

Our PIE savings vs bank savings calculator works that comparison in detail, including the bank rate that would be needed to match a given PIE.

Everything Above The Fund Is A Different Question

This page is about money that has to be reachable. Money beyond that is not governed by access at all, and holding it in cash has its own cost.

An after-tax return of 1.80% against inflation can easily be negative in real terms, which is a slow loss rather than a safe outcome. Our cash drag calculator prices that, and our savings to investment switch calculator addresses the horizon at which moving stops being a gamble.

Related NZ Savings and Cash Calculators

• Emergency Fund Calculator: how large the fund should be.
• PIE Savings vs Bank Savings Calculator: the PIR advantage in detail.
• Mortgage Offset Calculator: what offsetting does to the loan.
• Term Deposit vs PIE Fund Calculator: for money with a known date.
• Cash Drag Calculator: what holding cash costs beyond the fund.
• Emergency Fund Guide: background on this topic.