I think the two things are what do you want to do and where are you in your career? Being at Google is the safe easy money and will most likely work out better

I think the two things are what do you want to do and where are you in your career? Being at Google is the safe easy money and will most likely work out better than your startup from an odds perspective. However, you'll be a cog in a very large company whereas the startup you'll probably be able to have a huge impact in (presumably if you're getting 6% in options, that's like first/second engineer there or you're an exec). If this is your first job one thing to consider is that having worked at Google definitely is a good spot on your resume, recruiters like it, you'll get reached out to by lots of other recruiters, it'll be super easy to find another job which can honestly be more challenging if you just have no name failed startups on your resume. There is probably also more potential for title advancement at the new startup also vs. google. In my mind Google is a lot of sure money and you get to have a small impact on something with potentially huge impact to the world/people/whatever Small startups are a very small chance of some amount of money on the levels of (car, house, fuck you) and you get to have a large impact on something that may or may not have any discernible external impact.