On the same 650.000 kr. gross, a worker takes home roughly 27 985 kr more per year in Sweden than in Denmark. That gap reflects the tax structure alone — before rent, healthcare, or savings behaviour come into play.
Housing is the first multiplier. Denmark has high rent pressure, while Sweden has 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. Denmark runs a universal healthcare model — Universal tax-funded healthcare; very low out-of-pocket costs. Sweden uses a universal model — Universal regional healthcare with capped patient fees. 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 comprehensive welfare state in Denmark against comprehensive welfare state in Sweden, plus differences in pension capture, social safety nets, and city-level cost of living.