FAQs

For answers to other questions, do just strike up a discussion with classmates!

Does CS50x have a test or quiz?

Nope! CS50 at Harvard University and Yale University does have a test and quiz, but CS50x does not.

Does CS50x have office hours?

No, afraid CS50x is too large, but you can still start a discussion with classmates!

Does CS50x have sections?

No, afraid CS50x is too large, but you can still start a discussion with classmates!

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.

If you find yourself really struggling with the “more comfortable” version, you should switch to the “less” version (or if you’ve already completed that, simply move on and perhaps revisit in a later week). It would be better for you to skip the problem than to become so frustrated as to drop out of the course entirely. For reference, in the Fall 2019 Harvard class, only 20-30% of students submitted the “more comfortable” problems.

You don’t get any extra points for doing the “more comfortable” problems. If you submit both, the one with the highest grade will count towards your overall course progress.

I submitted a problem and did not reach the 70% passing grade! Can I resubmit?

Yes! You may resubmit; we will only count your most recent submission towards your progress.

Do I have to choose Verification before starting the course?

Nope! If you would like an edX Verified Certificate, you can pay for verification at any point, even after completing all of the coursework. (Though we recommend, to avoid any logistical issues that can delay certificate issuance, that you verify before finishing the course.)

If I paid for a verified certificate before 2020, do I need to pay again?

No, your verification should be good for an entire year, but if it has expired, you should be able to re-verify yourself via edX’s dashboard.

If I started CS50x before 2020, can I resume?

Yes, any progress you made on past years’ problem sets has been carried forward to your CS50x 2020 gradebook. Note that individual problem scores from past years are not shown, but if the corresponding problem set was completed, you’ll see it marked with a green circle and included in your progress bar at the top. Moving forward, though, you must submit CS50x 2020’s problem sets.

Here is how you should transition from the 2019 course to the 2020 course:

Completed in 2019 Resume your studies with Notes
No Problem Sets Week 0 and Problem Set 0 of CS50x 2020.  
Problem Set 0 Week 1 and Problem Set 1 of CS50x 2020.  
Problem Sets 0 - 1 Week 2 and Problem Set 2 of CS50x 2020.  
Problem Sets 0 - 2 Week 3 and Problem Set 3 of CS50x 2020.  
Problem Sets 0 - 3 Problem Set 3 in Week 3 then skip to Week 5 and Problem Set 5 of CS50x 2020. you may skip Problem Set 4
Problem Sets 0 – 4 Problem Set 3 in Week 3 then skip to Week 6 and Problem Set 6 of CS50x 2020. you may skip Problem Sets 4 & 5
Problem Sets 0 - 5 Problem Set 3 in Week 3 then skip to Week 6 and Problem Set 6 of CS50x 2020 your Homepage problem will count towards the Web Track after Week 8.
Problem Sets 0 - 6 Problem Set 3 in Week 3 then skip to Week 7 and Problem Set 7 of CS50x 2020.  
Problem Sets 0 - 7 Problem Set 3 in Week 3 then skip to Week 8 for CS50x 2020. after Week 8, choose your Track
Problem Sets 0 - 8 Problem Set 3 in Week 3 then skip to the Final Project of CS50x 2020.  

I won’t be able to finish the course before 31 December 2020. What will happen?

On 1 January 2021, the course will be updated to a 2021 version. Your progress from 2020 will be carried forward to the 2021 version (see below). After 31 December 2020, you may only submit the 2021 version’s problem sets and will need to satisfy whatever requirements are in place for CS50x 2021.

Will work I completed as part of CS50x 2020 carry forward into CS50x 2021?

Soon after 1 January 2021, equivalence credits will be given for work done in CS50x 2020 as follows. Note that you must have completed1 each row in a box in the left column before 1 January 2021 in order to receive credit for the corresponding problem set(s) in the right column. If you have only completed some of the items in a box in the left column, no equivalence credit will be given for that work. (The carryover is done on a per-problem set basis, not a per-problem basis; your individual problem scores will not carryover.)

Completed1 in CS50x 2020 Credit equivalent in CS50x 2021
Scratch Problem Set 0
Hello
Mario (Less) OR Mario (More)
Cash OR Credit		 Problem Set 1
Lab 1
Readability
Caesar OR Substitution		 Problem Set 2
Lab 2
Plurality
Runoff OR Tideman		 Problem Set 3
Lab 3
Filter (Less) OR Filter (More)
Recover		 Problem Set 4
Lab 4
Speller Problem Set 5
Lab 5
Hello
Mario (Less) OR Mario (More)
Cash OR Credit
Readability
DNA		 Problem Set 6
Lab 6
Houses
Movies		 Problem Set 7
Lab 7
Fiftygram (Android)
Pokedex (Android)
Notes (Android)		 Problem Set 8
Lab 8
Problem Set 9
Lab 9
Pong
Mario		 Problem Set 8
Lab 8
Problem Set 9
Lab 9
Fiftygram (iOS)
Pokedex (iOS)
Notes (iOS)		 Problem Set 8
Lab 8
Problem Set 9
Lab 9
Homepage
Finance		 Problem Set 8
Lab 8
Problem Set 9
Lab 9
Final Project Final Project

1 By completed, we mean you earned a 70% or better on the problem before 1 January 2021.

Will work I completed as part of CS50x 2019 (or older) carry forward into CS50x 2021?

Work completed in CS50x 2019 or prior is not subject to carry-forward for progress. Only work completed in CS50x 2020 will carry forward. This means if you received an equivalence credit that carried forward into CS50x 2020, that credit will no longer be valid as of 1 January 2021, and you may need to redo some assignments.

Is my child too young to take CS50x?

CS50x is perhaps best suited for ages 12 and up. Some of the software tools that the course uses require a minimum age of 13 to sign up. Therefore, younger students might need a hand from a parent in getting set up.

How do I know if I have completed all requirements for a certificate?

cs50.me/cs50x shows the scores you have received for each submitted problem. Once you have completed all requirements, you will see a green banner atop that page, confirming your completion.

How do I get my free CS50 Certificate?

Once you have completed the course and met all of the requirements, you’ll see a link on your cs50.me/cs50x page allowing you to request a free CS50 Certificate, much like the one shown here. This link will be available within approximately four hours. If you have trouble accessing it, try logging out of GitHub and back in, then revisit the link to download your certificate.

How do I get my edX Verified Certificate?

Every few weeks, CS50’s staff provides edX with a list of students who have satisfied CS50x’s requirements (by receiving scores of at least 70% on every required problem submitted as part of the course’s nine problem sets as well as on the final project). Typically within a week thereafter, edX then generates students’ Verified Certificates (for students who have active Verification), at which point they should appear automatically on edX’s dashboard. Note that edX will not notify you, so be sure to check your dashboard periodically.

If it has been more than a month since you met all requirements and you have still not received your certificate despite holding an active Verification that whole time, email certificates@cs50.harvard.edu with your details. Please do not email sooner; we cannot accept requests for expedited processing of Verified Certificates.

What’s the difference between a verified certificate and a CS50 Certificate?

A verified certificate, which you can purchase from from edX, “can provide proof for an employer, school, or other institution that you have successfully completed an online course. Verified certificates require you to verify your identity using a webcam and a photo identification card, so employers and schools know that you completed the course work.”

A CS50 Certificate is a free certificate from CS50 itself; CS50 does not verify identities.

When are deadlines?

CS50x does not have individual deadlines for problem sets or for the final project. You are welcome to work on and submit at your own pace. If all required work is turned in and received a satisfactory grade or before 31 December 2020, you will be considered to have completed CS50x 2020.

My Style grade is not what I expected. Why might that be?

Your style grade will be based on the style50 results for every source code file in your submission. When you run submit50, be sure that your folder includes only those files that are necessary for the problem set. If you have any extra test files in there, those will be counted towards your grade. Remove the extra files from the folder and resubmit to get an updated Style score.

Why does edX think my grade 0%?

CS50x doesn’t use edX’s built-in gradebook, so all students’ scores appear (in edX’s gradebook) as 0%, always. Not to worry, see cs50.me/cs50x for your actual scores.