In Sweden I always heard the figure to double the income of the person to get what the company actually pays, including taxes and "employers fee". I know this has gone down a lot in recent years, also not sure if it was ever exactly true, but likely very close anyway.

Hitting the first calculator I found gave me 50 kSEK costs 69 kSEK. So far from double nowadays.

Not doubting this at all but could you (or someone else) break this down for the sake of my curiosity?

I understand pension contributions, but what are the other "hidden" costs that could equal the net salary?