Cost of living in Aveiro (Portugal) is 21% more expensive than in Gdańsk (Poland)
This comparison has some inconsistent or sparse data. It already provides a reliable comparison but it is not bullet-proof. It is based on 339 prices entered by 56 different people.
For example, you would need at least 12,057 zł (€2,815) in Aveiro to maintain the same standard of living that you can have with 10,000 zł in Gdańsk.