Whether you are advancing your tech career or transitioning into the tech sector, online computer science classes provide you with the education you need. Many courses have little to no cost and allow you to study at your own pace. Online classes like the ones here provide you with theoretical and practical computer science knowledge and skills in a convenient and accessible way. 

Why take an online computer science class?

Learning about how computer software and hardware work gives you the tools to work in the world of information technology. Online computer science classes offer both personal and professional rewards. Many online courses in computer science are massive online open courses (MOOCs) that come from top universities worldwide through websites like Coursera and edX.

  • Courses may be part of certificates in areas — such as software engineering and computer security and networks — that you can add to your resume.
  • They allow you to pursue personal interests while growing your career.
  • You can study at your own pace.
  • Online computer science courses range from introductory to advanced.
  • You can learn computer programming languages like Python, C++, and Java.
  • Computer science courses online train you in computational thinking, how coding works, software design, and game development.

Free computer science classes: Our picks

Our list of online computer science courses starts with introductory classes and move into intermediate and advanced topics. Many of the latter require knowledge of computer science or prerequisite coursework and are ideal for individuals working in technology. Across the board, each online computer science class includes quality information presented at no cost. 

Online intro to computer science classes

Computer Science 101

  • Offered by: Stanford University via edX
  • Certificate? No; free to audit, pay to verify
  • Length and format of course: The six-week course allows for self-paced study and includes lab and video lecture components.

Who will benefit from this course? This course introduces you to computer software and hardware fundamentals, computer security, and how the Internet works. It is designed for individuals with no experience in computer science. 

What you’ll learn: You learn computer jargon, how software and hardware function, and the ins and outs of computer coding. Additional information about structured data, digital media, and big ideas accompany multiple-choice assessments and lab activities to build coding skills.

CS50’s Introduction to Computer Science

  • Offered by: Harvard University via edX
  • Certificate? Yes; free to audit, pay to upgrade
  • Length and format of course: The course lasts 6-12 weeks, depending on your self-study pace. Videos accompany assessment presented as problems sets.

Who will benefit from this course? As an introductory course on the fundamentals of computer science and programming, individuals with little or no previous experience benefit from the course. You receive the same content as students enrolled in Harvard’s identical on-campus offering. 

What you’ll learn: With an emphasis on topics like algorithms, data structures, software engineering, and web development, the class also teaches you programming languages. By using Python, HTML, JavaScript, and others, you gain the ability to develop and present a final programming project.

Intro to Theoretical Computer Science

  • Offered by: Udacity
  • Certificate? No, free
  • Length and format of course: The self-paced course lasts roughly two months. Taught by industry professionals, the format includes videos and interactive quizzes.

Who will benefit from this course? This course teaches you basic concepts of computer science theory. It is designed for individuals with little or no previous knowledge and experience.

What you’ll learn: Course topics build problem-solving and analytical skills to identify, understand, and reconcile problems that can be solved using soundness and completeness. You learn about tools and techniques to solve theoretically impossible problems, accepting randomness and approximations while recognizing the limits of computers to solve problems.

Introduction to Computer Science and Programming Using Python

  • Offered by: Massachusetts Institute of Technology via edX
  • Certificate? No; free to audit, pay to upgrade
  • Length and format of course: As the first of a two-course sequence, the class lasts roughly nine weeks of an instructor-led course schedule. 

Who will benefit from this course? If you want to know more about using Python 3.5 to solve real-world analytical problems, this class prepares you to do just that. This first course of a two-part sequence prepares you to continue onto a class in computational thinking and data science. You should have some high school mathematics aptitude and some background in programming. 

What you’ll learn: The class covers computational notions, the Python programming language, and how to use Python to solve algorithms. You progress from simple algorithms to algorithmic complexity while learning about testing, debugging, and data structures. 

Introduction to HTML and CSS

  • Offered by: Alison
  • Certificate? Yes, free
  • Length and format of course: The class lasts between 1.5 and 3 hours, with four individual modules offered in a self-paced format.

Who will benefit from this course? This class is ideal for beginners who want to learn Hypertext Markup Language (HTML) and Cascading Style Sheets (CSS), two applications used to create web pages.

What you’ll learn: While learning HTML and CSS, you gain insight into setting up a webpage. The course explains HTML formatting and tags, defines CSS and style properties, and trains you to model and manipulate the placement of elements to create the look and feel of a website.

Introduction to Python

  • Offered by: Alison
  • Certificate? Yes, free
  • Length and format of course: Self-paced and exclusively focused on Python, this course lasts between three and four hours.

Who will benefit from this course? If you need or want to learn Python’s syntax and functions, this course trains you through coding lessons, demonstrations, and exercises. 

What you’ll learn: Three modules explore Python, the first of which focuses on Python and basic data types. The second module explores functions, variables, and errors of Python, while the third module emphasizes keywords, statements, and loops. You’ll have a comprehensive understanding of Python by the end of the course.

Online intermediate and advanced computer science classes

Algorithms, Part I

  • Offered by: Princeton University via Coursera via Class Central
  • Certificate? No, free to audit
  • Length and format of course: The class includes six weeks of material, with video content. Numerous languages are available as subtitles. Programming assignments accompany the videos.

Who will benefit from this course? Practicing programmers learn about algorithms and data structures to gain information about applications and scientific performance analysis of Java implementations. 

What you’ll learn: The class covers data structures, sorting, and searching algorithms. You learn to analyze algorithms and about stacking, queuing, and symbol tables. The course moves toward a focus on graph- and string-processing algorithms. 

CS50’s Web Programming with Python and JavaScript

  • Offered by: Harvard University via edX)
  • Certificate? Yes; free to audit, pay to upgrade
  • Length and format of course: Self-paced with video content, the class lasts 12 weeks. 

Who will benefit from this course? Designed to follow Harvard’s introductory course in computer science, this class requires prior programming experience in any language. 

What you’ll learn: The class uses hands-on projects to train you to write and use application programming interfaces, create user interfaces, and leverage cloud services. You’ll study database design, scalability, and security while using languages such as HTML, Python, and JavaScript.

Machine Learning

  • Offered by: Harvard University via Coursera via Class Central
  • Certificate? Yes; free to audit, pay to upgrade
  • Length and format of course: Through 11 weeks of content, you watch videos, complete readings, and take assessment quizzes.

Who will benefit from this course? Researchers, programmers, and computer science professionals learn essential aspects of machine learning and progress toward human-level artificial intelligence.

What you’ll learn: The goal of machine learning is to get computers to perform without being programmed. The class explores the concepts of supervised and unsupervised learning while teaching you about data mining and statistical pattern recognition. You learn to apply algorithms to smart robots, text understanding, and medical informatics.

Mathematical Thinking in Computer Science

  • Offered by: University of California San Diego via Coursera
  • Certificate? Yes; free trial option
  • Length and format of course: The class includes roughly 40 hours of video content. You will solve interactive puzzles as you apply ideas and concepts. Readings and quizzes supplement these features.

Who will benefit from this course? Designed for individuals who want to apply discrete mathematics to computer science, the course includes prerequisites in basic math and basic programming knowledge, specifically Python.

What you’ll learn: The class emphasizes making and identifying arguments using mathematical thinking. Tools and techniques of discrete mathematics, like recursion, induction, and mathematical logic language and rules, train you to write readable and precise code. 

This article was reviewed by Monali Mirel Chuatico

Monali Mirel Chuatico, a woman with long dark hair, smiles in a headshot.

In 2019, Monali Mirel Chuatico graduated with her bachelor’s in computer science, which gave her the foundation that she needed to excel in roles such as data engineer, front-end developer, UX designer, and computer science instructor.

Monali is currently a data engineer at Mission Lane. As a data analytics captain at a nonprofit called COOP Careers, Monali helps new grads and young professionals overcome underemployment by teaching them data analytics tools and mentoring them on their professional development journey.

Monali is passionate about implementing creative solutions, building community, advocating for mental health, empowering women, and educating youth. Monali’s goal is to gain more experience in her field, expand her skill set, and do meaningful work that will positively impact the world.

Monali Mirel Chuatico is a paid member of the Red Ventures Education freelance review network. 

Last reviewed on February 11, 2022.