CS50's Introduction to Computer Science

  • Free
  • Certificate included
  • Course certificate
  • Beginner
  • 11 weeks
Provider
Harvard
Cost
Free
Certificate
Included, free and verifiable
Level
Beginner
Duration
11 weeks
Effort
10–20 hrs/week
Format
Self-paced
Language
English
Subjects
Computer Science, Programming
Source
Harvard Online
Last verified
14 Sep 2026

CS50x is Harvard's entry-level course in computer science and programming, open to people with or without prior coding experience. It begins with C, using it to introduce functions, variables, conditionals, loops, and how computers manage memory, then moves to Python, and finishes with SQL for databases and HTML, CSS and JavaScript for web and mobile apps, with a week on Flask. Each of the eleven weeks of material follows the same routine: watch the lecture, then the recommended section and shorts, then submit a problem set. The course ends with a final project of your own design.

Everything can be taken for free through the OpenCourseWare site; submitting problem sets for feedback requires a free edX account. Scoring at least 70% on every problem set, lab and the final project earns a free CS50 Certificate, issued through a unique URL. A verified certificate is available from edX for a fee for those who want a credential backed by edX's identity-verification process. Harvard's course listing states a time commitment of 10 to 20 hours per week and rates the course introductory.

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What you’ll learn

  • Think algorithmically and reason about correctness, design and style when solving problems
  • Write C programs using functions, variables, conditionals, loops, arrays and memory management
  • Implement and compare fundamental algorithms and data structures
  • Move from C to Python and use it for higher-level programming
  • Store and query data in relational databases with SQL
  • Build web applications with HTML, CSS, JavaScript and Flask
  • Complete a self-directed final project

Who it’s for

Anyone who wants a real grounding in how computers and programs work before specialising; not the shortest route if you only want to learn one language quickly.

Source: Harvard Online (opens in a new tab) · Verified · Report a change

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