Work /
Gross Salary 20000 PLN in Poland [9]
Far too complicated a question. It all depends on whether your wife will work, whether you will submit tax returns jointly, whether you will get 500+ for children.
As for savings it is a piece of string. How are we to know if you expect to eat out in the most expensive restaurants every day, once a week, never, or if your wife is a good cook and can make a meal out of nothing. What about schooling for your children? Where will they go? if to an English establishment then you will pay a high price.
Do your research well before you decide.
Salary of 20K pln gross per month sounds good,. but out of that you need to factor in accommodation, car usage, bills for gas/electricity/telephone, private medical insurance, clothing and everything else. No one can tell you these costs, some like heat at a higher level than others. Winters are terrifically cold.
This is not the same as if a Polish person was getting this salary, they have a family network who can invite them for dinner, help them with things. You will have no one.