Have Polish address - need postal code

I recently visited my polish girlfriend. I stayed at her place for awhile but never thought of asking for her postal code. I would like to send her a card for her birthday later this month but don't want to ask her or she'll expect something and it won't be a surprise. Any help?

Just google her street name and the name of her city, Polish post codes are pretty big.

Got that. I can find it on google maps but it doesn't show the postal code :/

Not google maps, google web search. There is almost certain to be somebody running a small business or something on her street and from their info you can find the postal code (hers is very likely to be the same).

use google search add the phrase "kod pocztowy" after the address and you should find it

Got it. Thank you!!