The Basics
If you were to hop on over to AP Central and look at College Board’s official descriptions of AP Calc AB and AP Calc BC, you might be surprised to see that the courses are described exactly the same way. If that were the case, why bother having two courses at all? The difference lies in the amount of material covered.
AP Calc AB covers one semester’s worth of introductory college level Calculus work, whereas BC covers two semesters worth. The topics covered in both courses are very similar, with BC naturally covering a few extra topics (like advanced integration methods, parametrics and vector differentiation, and sequence and series) on top of what AB can cover. Everything that would be taught in AB is also taught in BC.
The AP Calculus courses focus on differential and integral calculus as applied to reallife scenarios. Students learn to problem solve through multimedia such as graphs, numerical data, analysis, and word problems. They back up their conclusions with concepts such as change, differentiation, and limits.
The Exams
The two exams actually follow the same format, though there will be some slight changes in 2021 to account for digital test taking. The digital test changes will be included at the end of this section, after the the paper test format, as follows:

Multiple Choice: 45 questions in 1 hour 45 minutes. [50% of score]

Part A: 30 Questions in 60 minutes (calculator not permitted).

Part B: 15 questions in 45 minutes (graphing calculator required).


Free Response: 6 questions in 1 hour 30 minutes. [50% of score]

Part A: 2 questions in 30 minutes (graphing calculator required).

Part B: 4 questions in 60 minutes (calculator not permitted).

At least 2 of the questions will rely on analysis of real world scenarios.

On the 2021 digital exam, wherever calculators are not permitted, the questions will be formed so that use of a calculator would not even be helpful.
The Statistics*
AP Calculus AB

300,659 students took the AP Calc AB exam in 2019.

Of those students who took the exam, 58.4% scored a 3 or higher.

The mean score was a 2.97.

19.15 scored a 5 (19.5% in 2020).
AP Calculus BC

139,195 students took the AP Calc BC exam in 2019.

Of those students who took the exam, 81% scored a 3 or higher.

The mean score was a 3.8.

43% scored a 5 (44.6% in 2020)!
Right now, you’re probably thinking that those percentages for AP Calc BC can’t possibly be right. How could nearly half of the students be getting 5s, when AP Calc BC is supposed to be the more difficult course with more material? There are many theories about this ranging from testing curves to questions types, but the simplest answer is that students who choose to take AP Calc BC are a far smaller community who are already extremely advanced in math. They may have taken Calculus I or even AP Calc AB the year before, laying a very strong foundation for BC.
*All statistics are sourced from College Board 2019 & 2020 score distributions
Additional Course Facts

AP Calc AB is more often taken as a senior, but in 2019 nearly half as many students chose to take it junior year as did in senior year. AP Calc BC is most often taken in senior year.

Some colleges will accept a passing AP score as college credit, which can decrease college costs. AB can earn credit for Calculus I at most schools; BC may be able to cover both Calculus I and II.

College Board is introducing some changes to most AP Exams in 2021, so make sure you’re looking at the new formats when you’re practicing!
Why should you take either of these courses?
It goes without saying that either AP Calculus course is excellent for students considering going into any sort of mathematical or scientific field. Taking these courses ahead of time will allow you to jump into the more advanced math courses in college and really kickstart your education. It’s a great leg up! Calculus is used in so many fascinating fields, ranging from software design and electrical engineering to chemistry and economics!