CS50’s Python course introduces programming with Python, covering code reading and writing, testing, debugging, and core concepts.
CS50
CS50x is Harvard’s introduction to computer science and programming for students with or without prior experience.
About CS50
CS50x 2026 is Harvard University's introduction to computer science and the art of programming. It is designed for concentrators and non-concentrators alike, with or without prior programming experience. Topics include computational thinking, abstraction, algorithms, data structures, correctness, design, and style, with problem sets inspired by the arts, humanities, social sciences, and sciences.
The course starts with C to cover functions, variables, conditionals, loops, memory, and how computers work. It then moves to Python, followed by SQL for databases and HTML, CSS, and JavaScript for web and mobile apps. Learners can work through eleven weeks of lectures, sections, shorts, and problem sets, then complete a final project. Non-Harvard learners can take the material for free via OpenCourseWare, and lectures are available in English, Portuguese, and Spanish.
It suits beginners and non-computer science students who want a structured introduction, as well as teachers who want to adopt the materials. Submitting problem sets for feedback requires an edX account, while verified certificates and transfer credit require separate enrollment.
Key features
- Eleven weeks of lectures, sections, shorts and problem sets
- Starts with C, then Python, SQL, HTML, CSS, JavaScript
- Final project to complete at end of course
- Lectures available in English, Portuguese and Spanish
- Free OpenCourseWare access for non-Harvard learners
- Materials teachers can adopt or adapt for courses
Best for: Beginners with or without prior programming experience who want an introduction to computer science.
Good for
- Free access to eleven weeks of course material
- Covers C, Python, SQL, and web technologies
- Designed for learners without prior experience
- Teacher materials and educator workshop available
Watch out for
- Problem set feedback requires an edX account
- Certificates and transfer credit require separate enrollment
CS50 at a glance
- Website
- cs50.harvard.edu/x
- Category
- Education & Learning › Learn to Code
- Type
- Website
- Pricing
- Free
- Platforms
- Android, iOS, Web
- Open source
- Not stated
- Language
- English
- Last checked
- Oct 6, 2026 · Online when checked
- Listed
- Oct 5, 2026
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CS50 FAQ
Is CS50x free?
Yes, non-Harvard learners can work through the eleven weeks of material for free via OpenCourseWare. An edX account is needed to submit problem sets for feedback.
Do I need prior programming experience for CS50x?
No, the course is for learners with or without prior programming experience. Two thirds of CS50 students have never taken CS before.
What programming languages does CS50x cover?
It starts with C, then moves to Python, and later introduces SQL, HTML, CSS, and JavaScript.
How do I get a certificate or credit for CS50x?
Verified and professional certificates require separate enrollment through edX. Transfer credit requires registration through Harvard Extension School or Harvard Summer School.
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