Email heads@cs50.harvard.edu with any other questions!


How should I structure my week?

Most weeks follow the pattern below.

Monday lecture  
Tuesday class quiz
Wednesday sections, tutorials  
Thursday tutorials lab
Friday tutorials  
Saturday tutorials  
Sunday tutorials problem set

Accordingly, plan to

  1. watch lectures on Mondays,
  2. submit quizzes by Tuesdays,
  3. attend class on Tuesdays,
  4. submit labs by Thursdays,
  5. optionally attend tutorials on Wednesdays, Thursdays, Fridays, Saturdays, and/or Sundays, and
  6. submit problem sets by Sundays.

College Requirements

Does CS50 satisfy any College requirements?

Yes. You may take CS50 (SAT/UNS or for a letter grade) to fulfill the Science and Engineering and Applied Science distribution requirement or the Quantitative Reasoning with Data requirement, but not both.


Will everyone else know more than me? Less than me?

Not at all! Approximately two thirds of CS50 students have never taken a CS course before. Moreover, in Fall 2020, 53% of students described themselves as among those less comfortable, while 16% described themselves as more comfortable, and 31% described themselves as somewhere in between. No matter your own comfort level, then, you’ll be in good company!

comfort level


How does this year differ from past years?

CS50 has long been offered online in some form, so this year won’t be all that different, all things considered! Lectures, of course, won’t be in person but online via Zoom, as will be sections and tutorials. And there won’t be a CS50 Hackathon or CS50 Fair. But there will still be CS50 Puzzle Day, CS50 Meals (a la Classroom to Table, albeit via Zoom), and more, all at a healthy distance!


Does CS50 still have end-of-term tracks?

In Fall 2019, CS50 offered a choice of lectures and problem sets at term’s end on web programming, mobile app development, and game development. It turned out that most students chose the track on web programming, so we’ve reverted to focusing on web programming as of Fall 2020!

Which languages will I learn?

Rather than teach just one language, CS50 introduces students to a range of “procedural” programming languages, each of which builds conceptually atop another, among them Scratch, C, Python, SQL, and JavaScript. Along the way does the course also introduce students to HTML and CSS (which are languages but not programming languages). The goal, ultimately, is for students to feel not that they “learned how to program in X” but that they “learned how to program.”

Why does CS50 use C?

See this answer on Quora!

First Years

Can first years take both CS50 and a Freshman Seminar SAT/UNS?

Yes. Even though first years may not ordinarily enroll in both a Freshman Seminar and another non-letter-graded course in any one term, they may take both CS50 and a Freshman Seminar SAT/UNS.

Should first years take CS50?

Yes, if they would like! In Fall 2019, first years composed a plurality of CS50’s student body. While students should be mindful of CS50’s workload and should perhaps avoid taking 4 pset-based classes, students shouldn’t shy away (from CS50 or any other introductory course) simply because they’re first years.


How can I change from SAT/UNS to letter grade?

If you are a College student, submit a Grading Basis Change Request form no later than , the term’s eleventh Monday.

If you are a grad student or cross-registered, email enrollment@fas.harvard.edu no later than , the term’s eleventh Monday, and FAS’s Registrar will make the change for you.

How can I check the status of my Grading Basis Change Request?

If you are a College student, see step 5 of the Change of Grading Basis Workflow.

Should I take CS50 SAT/UNS or for a letter grade?

Unless your (potential) concentration requires that you take CS50 for a letter grade, you should take CS50 SAT/UNS, which is the default. Not only does SAT/UNS allow you to explore an unfamiliar field (whether CS or some other) without fear of “failure,” odds are, more pragmatically, it will reduce undue stress during your semester’s busier times.

What is CS50’s grade distribution?

Per CS50’s syllabus, “what ultimately matters in this course is not so much where you end up relative to your classmates but where you, in Week 11, end up relative to yourself in Week 0.” Accordingly, provided you put in the time and effort, odds are you’ll fare quite well! In Fall 2019, 34% of students received a final grade of SAT, 34% of students received a final grade of A, 20% of students received a final grade of A-, 8% of students received a final grade in the B range, and 2% of students received a final grade in the C range, per the below. In cases of E (<1%) or UNS (1%) were typically extenuating circumstances.


Which concentrations offer concentration credit for CS50?

See this spreadsheet.

Which concentrations require a letter grade in order for CS50 to count for concentration credit?

See this spreadsheet. Note that you may take CS50 SAT/UNS and concentrate in CS; CS does not require a letter grade.

Prior Experience

Does CS50 have any prerequisites?

No, CS50 does not assume any prior CS or programming experience. In fact, 60% of Fall 2019’s students had never taken a CS course before!

Should I skip CS50 if I already took AP CS A?

Probably not. Most students who have taken AP CS A still take CS50 as it tends to fill in gaps in their knowledge and also introduces them to C (and more!).

Should I skip CS50 if I already took AP CSP?

Probably not, unless you took CS50 AP.

Problem Sets

What’s the difference between “less comfortable” and “more comfortable” problems? Do I have to do both?

In some earlier problem sets, you’ll have a choice between a “less comfortable” and a “more comfortable” problem.

The “less comfortable” are what you might consider the “standard” version of the problem, designed for students who have little or no prior experience. The “more comfortable” are the “challenge” version, designed for students who consider themselves more comfortable due to prior study/experience before this class. As such, they may require more concepts than have been covered in the course so far.

You don’t get any extra points for doing the “more comfortable” problems. If you submit both, we will consider the one with the highest score. For reference, in Fall 2019, 20-30% of students submitted the “more comfortable” problems.


Is attendance at section expected?

Yes, as sections are meant to be a more intimate, interactive opportunity to master the course’s material.


When is CS50 offered?

CS50 is offered primarily in fall term. All students, including concentrators and non-concentrators, are encouraged to take CS50 in fall term. However, concentrators and secondaries unable to take the course in fall term may take the spring or summer version of CS50.

How do spring term (at Harvard College) and summer term (at Harvard Summer School) differ from fall term (at Harvard College)?

The spring version of CS50 is for SEAS concentrators (or secondaries) who are unable to take the course in fall term. All students, including concentrators and non-concentrators as well as cross-registrants, are encouraged to take CS50 in fall term instead.

In fall term, students are expected to attend live lectures via Zoom as well as live sections via Zoom. In spring term and summer term, students are expected to watch lectures on video (produced in fall term) and attend live sections via Zoom.

Academically, the terms are equivalent, but the fall version of CS50 includes cultural traditions as well.

  Fall Spring Summer
CS50 Meals    
CS50 Puzzle Day    
Enrollment Unlimited Limited Unlimited
Final Project
Grading Basis SAT/UNS or letter SAT/UNS or letter SAT/UNS or letter
Lectures Live Video Video
Meetings TF-led sections Preceptor-led classes Preceptor-led classes
Meetings per Week 1 1 2
Office Hours
Problem Sets
Simultaneous Enrollment    


How difficult is CS50?

For many students, CS50 is simply more time-consuming than it is difficult. Starting each week’s problem set early, then, makes things easier! And the course’s difficulty was also recalibrated back in 2016, per the Q data below.


How much work is CS50?


By mid-semester, most students spend 10+ hours per week on the course’s problem sets, but it definitely varies by student and by problem set, per the below data from Fall 2020.