Retirement & the 4% Rule
Translate an income gap into an illustrative savings target.
All amounts NZD · Examples are editable · Entries stay in this browser session and are not saved
Your weekly income goal
Use a withdrawal rate that leaves spendable income after taxes and fees. This model does not separately calculate either.
$450 × 52 ÷ 4% = $585,000.
| Withdrawal assumption | Required capital |
|---|---|
| 3% | $780,000 |
| 4% | $585,000 |
| 5% | $468,000 |
So what does this actually mean?
Your other income leaves $450 a week to fund. At a 4% spendable withdrawal rate, that implies around $585,000 of starting capital.
The “4% rule” commonly describes withdrawing 4% of the initial portfolio, then adjusting that dollar amount for inflation. This tool only estimates a starting target; it does not simulate that strategy or guarantee that money lasts.
A lower withdrawal rate or higher spending goal increases the target. Higher assumed withdrawals lower the target but can increase the risk of running out. Investigate retirement length, housing, healthcare, tax, fees, inflation and market downturns with a qualified adviser.
Understand this tool
What this calculator is showing you
Your weekly income gap multiplied by 52, divided by a chosen withdrawal percentage. This estimates a starting pool of savings, not a retirement-income guarantee.
How to use it
- Enter your desired after-tax weekly income, expected after-tax NZ Super or pension and other regular after-tax income.
- Choose a spendable annual withdrawal rate.
What the result means
For example, $1,000 a week minus $550 pension leaves $450, or $23,400 a year. Dividing by 4% gives $585,000. A lower withdrawal assumption requires more starting capital.
Things this calculator does not know
Longevity, investment losses early in retirement, inflation, tax, fees, healthcare, housing, inheritance and policy changes. The model treats the rate as money available to spend after any taxes and fees; a quoted gross withdrawal rate may not provide this income.
Try changing this
Compare 3%, 4% and 5%. Then change your weekly spending target. Consider a qualified adviser and a more detailed drawdown plan before relying on a withdrawal strategy.
Scenario prepared 30/10/2026. Assumptions and results are illustrative.