Cost of living in Kazan' (Russia) is 24% more expensive than in Łódź (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 596 prices entered by 38 different people.
For example, you would need at least 7,816 zł (руб 131,346) in Kazan' to maintain the same standard of living that you can have with 6,300 zł in Łódź.