This New Zealand calculator shows how long a retirement lump sum lasts at a chosen withdrawal rate and return. Drawing more than your savings earn means the balance falls and eventually runs out; drawing less can let it last indefinitely. You enter your lump sum, annual withdrawal, expected return and inflation, and the tool estimates the years your money lasts, so you can set a spending level your savings can sustain.
Withdrawals rise each year with inflation to keep your buying power steady. If the return covers withdrawals, the savings can last indefinitely. This ignores tax and NZ Super, which is a separate income on top. Estimate only, not financial advice.
The calculator steps through each year, growing the balance by the expected return, then taking out your withdrawal, which it increases each year by inflation so your buying power stays steady. It counts the years until the balance hits zero. If the return comfortably covers the withdrawals, the balance holds or grows, and the result shows the savings can last indefinitely at that rate.
A $500,000 lump sum with $30,000 a year withdrawals is a 6% withdrawal rate. At a 4% return with 2.5% inflation, the savings last around 20 years before running out. Dropping the withdrawal to $20,000, a 4% rate, would make the money last far longer or indefinitely.
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