Variable vs Fixed Drawdown in Retirement (NZ, 2026): How to Decide How Much to Take Each Year

Fixed-dollar, fixed-percentage or guardrails? Here is how the main retirement drawdown methods behave in good years and bad ones, and how to set up flexible payments from a KiwiSaver in NZ.

Once you stop earning, the question changes. It is no longer "how much can I save", but "how much can I safely take out each year without running short". The method you choose to set that figure matters as much as the size of your pot. This guide compares the three approaches most New Zealanders use, and how each one behaves when markets fall.

TL;DR: A fixed drawdown pays you a set, inflation-adjusted dollar amount each year, so your income is steady but you keep selling units in a falling market. A variable method (a fixed percentage, or "guardrails") flexes your income with the balance, which protects the capital but means your income moves. The 4% rule is the common starting point: take 4% of the pot in year one, e.g. $40,000 from $1,000,000. ⁷

What is the difference between a fixed and a variable drawdown?

A drawdown method is simply the rule you use to decide how much to withdraw each year. There are two broad families.

A fixed drawdown sets a dollar income and protects that income. You pick a starting figure, then lift it by inflation each year so your spending power holds steady. The trade-off is that the amount you take has no relationship to how your investments are doing. In a bad year you sell more units to fund the same income.

A variable drawdown sets a rule and protects the capital. Your income is recalculated each year from the current balance, so it rises when markets do well and falls when they do not. Your spending is less predictable, but your money is far less likely to run out, because you never keep drawing a large fixed sum from a shrinking pot.

Neither is automatically "right". A steady income is easier to live on; a flexible income is safer for the portfolio. Most of choosing a method is deciding which of those two you value more, and how much movement in your income you could actually absorb.

How does a fixed-dollar (inflation-adjusted) withdrawal work, and when does it fail?

This is the classic approach, and the one most people picture. The best-known version is the 4% rule: withdraw 4% of your portfolio in the first year, for example $40,000 from a $1,000,000 balance, then increase that dollar figure by inflation every year after. It was designed to last roughly 30 years with a growth-asset allocation in the 50-75% range. ⁷

Its strength is certainty. You know your income, it keeps pace with the cost of living, and you can budget years ahead.

Its weakness shows up when markets fall, especially early in retirement. Because the withdrawal is a fixed dollar amount, a market drop does not reduce what you take; it just means you sell a bigger share of a smaller fund to fund the same income. Doing that during a downturn locks in losses and leaves less invested to recover when markets turn. This is closely linked to sequencing of returns risk, where the order of good and bad years, not just the average, decides whether the money lasts.

There is a second, subtler issue. A flat inflation-indexed income assumes you spend the same in real terms at 85 as at 65. Te Ara Ahunga Ora's retirement income research found that spending tends to fall in real terms as people move through retirement. ⁶ A fully inflation-indexed fixed drawdown can therefore overstate what is actually needed in the later years.

How does a fixed-percentage withdrawal smooth out market falls?

A fixed-percentage method takes the same percentage of your balance every year, recalculated annually. Take 4% of $1,000,000 and you draw $40,000; if the balance falls to $850,000 the following year, 4% gives you $34,000.

The advantage is that you can never fully run out, because you are always taking a slice of what remains rather than a fixed lump from a shrinking pot. The percentage automatically dials your spending down in poor years and up in good ones, which keeps the capital intact through a downturn.

The cost is income volatility. In a year like the one to 31 March 2022, when FMA reported KiwiSaver investment returns fell sharply to $1.3 billion from $13.2 billion the year before, with default funds posting negative average returns, ⁵ a percentage method would cut your income noticeably at exactly the moment your other costs may be rising. For someone relying on that income to cover essentials, a sharp cut is hard to live with. It is safest for the portfolio but hardest on the household budget.

What are 'guardrails', and why do advisers like them?

Guardrails are a middle path, and the reason many advisers prefer them. You set a target income and let it rise with inflation as in a fixed plan, but you add two limits, an upper and a lower "guardrail", on the withdrawal rate.

In practice it works like this. If markets fall and your withdrawal rate drifts above the upper guardrail (you are now taking too large a share of a smaller pot), you trim your income, often by around 10%, to bring it back inside the rails. If markets do well and your rate drops below the lower guardrail, you can give yourself a modest pay rise. In ordinary years, you do nothing and your income simply keeps pace with inflation.

The appeal is that it keeps most of the predictability of a fixed income while borrowing the self-correcting safety of a variable one. You are only asked to change your spending when the numbers genuinely call for it, rather than every single year. The trade-off is that it is more involved to run; you need to review the withdrawal rate annually and actually make the cut when a guardrail is breached, which takes discipline.

How does each method behave in a bad year like 2022?

The table below is an illustration only. It models a $500,000 starting balance across a ten-year sequence that includes a sharp fall in year four, to show the central trade-off: a steady income versus a protected balance.

Illustrative modelling only, not a projection of any actual fund. Read across year four. The fixed-dollar plan holds your income steady but takes the biggest bite out of a fallen balance. The fixed-percentage plan protects the capital but cuts your income by around 13% in one year. Guardrails sit between the two, trimming income modestly only when the downturn pushes the withdrawal rate past the rail.

Which method protects against running out of money?

On the central question of longevity risk, the order is fairly clear.

• Best protection against running out: fixed percentage. Because the dollar amount always shrinks with the balance, the pot is mathematically very hard to exhaust. The price is the least predictable income.
• Strong protection with steadier income: guardrails. The trims kick in only when needed, so you keep most of the predictability while still defending the capital in a bad sequence.
• Weakest protection: fixed-dollar. Steady income comes at the cost of "sequencing" risk, drawing a fixed sum through an early downturn is what most often empties a portfolio ahead of schedule.

The honest answer is that no method removes the risk entirely; they manage it differently. NZ Super does a lot of the heavy lifting underneath whichever method you choose. A single person living alone receives $555.15 a week after tax (M code), ¹ a couple who both qualify receive $854.08 combined. ³ Because that base income is guaranteed for life and indexed each year, your drawdown only has to fund the gap above it, which makes a modest income cut in a bad year far easier to absorb than it first sounds. For more on setting the starting figure, see our guide to the safe withdrawal rate in NZ.

How do you set up variable payments from a KiwiSaver in NZ?

From age 65 you can withdraw from KiwiSaver, and you do not have to take it all at once. Several NZ providers offer scheduled regular withdrawals, weekly, fortnightly or monthly, paid straight from your fund, and these can usually be adjusted up or down or paused as your needs change. ⁸ That facility is what makes a variable or guardrails method practical to run rather than just a spreadsheet exercise.

A few practical points worth knowing:

• Stay invested while you draw. Your remaining balance keeps earning, which is what allows the pot to last decades. That also means returns are not guaranteed and the balance can fall.
• Keep contributing if you are still working past 65. Note that government contributions and employer contributions generally stop at 65, and the minimum employee and employer rate is 3% as at 10 October 2025, rising to 3.5% from 1 April 2026. ⁹
• A cash buffer helps. Holding a year or two of withdrawals in a lower-risk fund means you are not forced to sell growth assets in a falling market. This is the core idea behind a bucket strategy.
• Compare the facility, not just the fund. Providers differ in withdrawal frequency, minimums and flexibility. Our overview of KiwiSaver drawdown options walks through how the main schemes handle this.

How do you choose the right method for your situation?

There is no method that is best for everyone, but a few factors point you in a direction.

The deeper choice is not really mathematical; it is about how much income movement your household could genuinely cope with, and how your spending is likely to change as you age. Those are exactly the things a calculator cannot weigh for you. Many people choose a method, then review it each year and adjust, which is closer to how retirement income works in practice than picking one rule and never touching it again.

Frequently asked questions

What is the difference between fixed and variable drawdown?

A fixed drawdown pays a set, inflation-adjusted dollar income each year, so your spending is steady but you keep drawing the same amount even when markets fall. A variable drawdown (a fixed percentage, or guardrails) recalculates your income from the current balance, so it moves with the markets and protects the capital. One prioritises income certainty, the other prioritises making the money last.

Is the 4% rule safe to use in New Zealand?

The 4% rule is a common starting benchmark, take 4% of the pot in year one, for example $40,000 from $1,000,000, then adjust for inflation, designed to last around 30 years with a 50-75% growth allocation. ⁷ It is a useful starting figure rather than a guarantee, and it does not account for NZ Super, your tax, your fees or how your spending changes with age. Returns are not guaranteed, so treat it as a benchmark to test, not a rule to follow blindly.

What are guardrails in retirement drawdown?

Guardrails set an upper and lower limit on your withdrawal rate. Your income rises with inflation in normal years, but if a market fall pushes your withdrawal rate above the upper rail you trim your income (often by around 10%), and if strong returns push it below the lower rail you can give yourself a small rise. It keeps most of the predictability of a fixed income while defending the capital in a downturn.

Can I set up regular automatic payments from my KiwiSaver?

Yes. From age 65 several NZ providers let you set up scheduled regular withdrawals, weekly, fortnightly or monthly, paid directly from your fund, and you can generally adjust or pause them as your needs change. ⁸ Availability and minimums vary by provider, so check the scheme's product disclosure statement.

Which drawdown method is least likely to run out of money?

A fixed-percentage method is mathematically the hardest to exhaust, because the dollar amount always shrinks with the balance, though its income is the least predictable. Guardrails come close while keeping a steadier income. A fixed-dollar income carries the most risk of running short if a market downturn hits early in retirement.

Does NZ Super change which method I should use?

It gives you more freedom. NZ Super is guaranteed for life and indexed each year, $555.15 a week after tax for a single person living alone, ¹ or $854.08 combined for a couple who both qualify. ³ Because that base income is secure, your drawdown only funds the gap above it, so an income cut in a bad year is easier to absorb than it might first appear.

General information, not personalised financial advice. Returns are not guaranteed; the value of investments can go down as well as up and you may get back less than you invested. Past performance is not a reliable indicator of future performance. Projections are illustrations based on stated assumptions, are not predictions, and actual results will differ. KiwiSaver is a long-term savings scheme; government contributions, contribution and withdrawal rules and tax settings are set by the Government and can change, figures are correct as at 10 October 2025. Seek advice tailored to your situation before acting. Craig Smith Business Services Ltd (FSP712931), trading as Smiths Financial, holds a Class 2 licence issued by the Financial Markets Authority and is a member of the Financial Dispute Resolution Service (FDRS). Written by Henry Smith, Financial Adviser; reviewed by Craig Smith, Principal Adviser. Last reviewed 10 October 2025.