Do colleges recalculate high school students' gpa according to the rigor? I know that they like AP and honors courses, but I'm not sure if or how they recalculate gpa when they are looking at our transcripts for admission.
For most colleges, there won't necessarily be a formal "recalculation" of your GPA to account for honors and AP/IB courses. Instead, admissions officers will consider the totality of your academic record. This not only means looking at the difficulty level of the courses you took, but at the trend over time. For instance, a student who starts out taking grade-level math and gets an A-, moves to honors math and gets a B+, and ends senior year by taking AP Calculus and getting an A- shows a trajectory towards more difficult coursework, even though her GPA doesn't necessarily change all that much.
Here's an example of how one liberal arts college's admissions officers consider a student's application (taken from a personal communication, with permission; bolding added by me for emphasis):
Wellesley does not recalculate any student's GPA. As we review holistically, we have the time to truly analyze a student's performance in high school. We really do not spend much time on the GPA (weighted or unweighted) as a pure number, instead we read each transcript line by line and look at the student's performance in each individual class. We pay close attention to the rigor a student has taken at their high school and how that is reflected on their transcript, but do not place a whole lot of value in their calculated GPA due to so many variations. We look for a student to have taken the highest rigor available whenever possible, whether AP, IB, A-level, etc and consider their high school performance alongside their standardized testing, recommendations, and essays.
The Wellesley admissions officer who was kind enough to answer my questions also pointed out that state schools and other schools more concerned with test scores and GPA (for scholarship or ranking purposes) may recalculate student GPAs in order to ensure students meet (relatively rigid) admissions and merit scholarship criteria. Therefore, I'd advise that if you are applying to a state school or to a school that provides merit scholarships for certain GPAs, you should contact the admissions office for that particular school to gain clarity on whether or not they recalculate applicants' GPAs (and if so, how they recalculate them).
For more information on this topic, be sure to read our article "Do Colleges Use Weighted or Unweighted GPA?"