A safe withdrawal rate is the percentage of your savings you can spend in the first year — then adjust for inflation each year after — with a high chance of the money lasting your whole retirement. The 4% rule is the well-known rule of thumb from US research: draw 4% of the starting balance, and historically it survived a 30-year retirement in almost every case.
The Australian twist
4% is conservative here, because Australia has a safety net the US doesn't: the means-tested [Age Pension](/learn/age-pension). As you draw your savings down, the pension grows to partly fill the gap — so a plan that would fail on savings alone often survives. The planner solves for *your* steady SWR given your balances, home ownership and the pension, and it's frequently 5–8%, higher for leaner portfolios that lean more on the pension.