Also, in several countries that I know of, there are websites (the one I have in mind is by a union, but I've seen others in the past) that list out in excrucia

Also, in several countries that I know of, there are websites (the one I have in mind is by a union, but I've seen others in the past) that list out in excruciating detail what sort of costs you need to take into account when setting your (minimum) rates. It varies quite a bit by country.