I've worked in finance for a medium-sized SF company and a small (~50 employee) startup in SV. Our standard assumption for 'all-in' employee cost was to add an additional 30% on top. For highly paid employees, this actually gets reduced a bit since FICA cuts off at $118k.

To get to $250k total outlay with an admittedly outdated spreadsheet, the salary would have to be $200k (benefit load of only 26%). Of course this depends greatly on PTO, Health Care, Worker's Comp, etc.