On the same 650.000 kr. gross, a worker takes home roughly 85 178 kr more per year in Norway than in Denmark. That gap reflects the tax structure alone — before rent, healthcare, or savings behaviour come into play.
Housing is the first multiplier. Norway has high rent pressure, while Denmark 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. Norway runs a universal healthcare model — Universal public healthcare with small patient co-pays. Denmark uses a universal model — Universal tax-funded healthcare; very low out-of-pocket costs. 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 Norway against comprehensive welfare state in Denmark, plus differences in pension capture, social safety nets, and city-level cost of living.