On the same 65 000 € gross, a worker takes home roughly 16 905 kr more per year in Norway than in Finland. 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 Finland has moderate rent pressure. That means part of the higher take-home in Norway can be absorbed by rent if you land in a major city.
Healthcare and pensions go in the opposite direction. Norway runs a universal healthcare model — Universal public healthcare with small patient co-pays. Finland uses a universal model — Public healthcare via wellbeing services counties; private add-ons exist. 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 Finland, plus differences in pension capture, social safety nets, and city-level cost of living.