<p>My understanding is that colleges do have their own system but do not keep it secret.
A few that I contacted said the same thing: they consider only core courses: English, social studies, math and science, maybe foreign languages. They do not include arts electives or PE.
Our high school does not weigh. A GC told me there was no point as colleges recalculate. However, high school GPAs do count for rankings and colleges (and scholarships) take rankings very seriously.</p>