I'm a senior web/fullstack developer, interviewing with some firms in order to move to the Valley. I have a good chance with a company in SF, soon I'll have to

I'm a senior web/fullstack developer, interviewing with some firms in order to move to the Valley. I have a good chance with a company in SF, soon I'll have to negotiate the salary with them. Is $120.000/year really hardly enough to live on there? I'm in Europe now so I really don't know the costs there. Here I make ~7000-9000 Eurs / month, which is quite enough.