Cost of living in Karlsruhe (Germany) is 26% cheaper than in Amsterdam (Netherlands)
This comparison is lacking data. It provides a decent comparison, but it is not yet reliable. It is based on 1,388 prices entered by 308 different people.
For example, to keep the same standard of living that would require €5,400 in Amsterdam you would need to make just about €3,973 in Karlsruhe.