Re:
Poslano od Herman F u Nizozemska forum
You can use this website to make a calculation: http://www.loonwijzer.nl/home/salaris/brutonetto
55k before tax (bruto) would be 27155 euro after tax (netto) so that would be 2263 euro after tax a month (approximately because of things like vacation money, which usually amounts for about one month of salary etc).
In the Netherlands, to make 4000 euro a month after tax you would have to earn 98427 euro a year before tax.