stanford/mit chances?

Chance Me / Match Me
1

grades: 3.98/4 unweighted, 4.51/4.8 weighted

test scores: 1570 sat (790 math / 780 reading), 800 math, 800 chem

ec’s/awards:
co-founded startup (~1mil funding but pre-revenue)
varsity/club soccer (12 yrs club, 3 yrs varsity)
research (siemens semifinalist)
science bowl captain (regional champions, made national playoffs)
Other math/science competitions (TEAMS national champions, USACO platinum, USAPhO HM, USAJMO qualifier, etc.)

what are my chances?

2

According to a recent article, Stanford’s acceptance rate for 2017 was 4.7%. MIT’s rate for 2016 was 7.9%.

I think that your chances are better than this average, but probably still well below 50%.