On the same $90,000 gross, a worker takes home roughly $4,010 more per year in Australia than in Singapore. That gap reflects the tax structure alone — before rent, healthcare, or savings behaviour come into play.
Housing is the first multiplier. Australia has very high rent pressure, while Singapore has very high rent pressure. The two markets behave similarly, so most of the gross-to-net advantage flows straight into disposable income.
Healthcare and pensions go in the opposite direction. Australia runs a universal healthcare model — Medicare gives universal access; private cover speeds up elective care. Singapore uses a mixed model — MediSave/MediShield is mandatory for citizens & PRs; expats use private cover. The country with lower take-home often shifts costs that the other country leaves to your private budget.
Net-of-everything, a relocation decision should weigh strong public welfare in Australia against balanced public welfare in Singapore, plus differences in pension capture, social safety nets, and city-level cost of living.