The 250 Best Free Online Courses of All Time – A Data-Driven Analysis [2021 Edition]

Over the past decade, the rise of Massive Open Online Courses (MOOCs) has transformed the educational landscape. MOOCs have made high-quality learning from top universities accessible to anyone with an internet connection, regardless of their location, background, or finances. As a full-stack developer who has personally benefited from MOOC courses, I‘m excited to share Class Central‘s ranking of the all-time top 250 free online courses. This data-driven list is a testament to the power of MOOCs to democratize education and create new opportunities.

Since the first MOOCs appeared in 2011, the number and variety of courses has exploded. Class Central, a search engine and review site for online courses, has tracked the growth of the MOOC industry from its inception. Today, Class Central‘s catalog includes over 50,000 courses from more than 950 universities and 60 different platforms. Over 180 million learners worldwide have enrolled in at least one MOOC [1]. That‘s equivalent to more than 2% of the world‘s population!

To create this ranking of the top free online courses, Class Central used a Bayesian average of the 50,000+ user reviews on their site. Courses were only included if they had at least 20 reviews. So which courses made the cut? Here‘s a high-level look at the top 250:

As you can see, the most heavily represented subjects are Technology (42 courses), Science (34 courses), Business (34 courses), and Humanities (38 courses). But the ranking covers a remarkably wide range of disciplines, from Art & Design to Education to Health & Medicine to Social Sciences. Whatever you‘re interested in learning, you‘re likely to find a high-quality free course on the topic.

As a professional developer, I‘m particularly excited by the large number of programming and computer science courses featured in the ranking. Many of the most popular courses overall fall into this category, including:

• Machine Learning (Stanford University via Coursera)
• AI For Everyone (deeplearning.ai via Coursera)
• Programming for Everybody – Getting Started with Python (University of Michigan via Coursera)
• CS50‘s Introduction to Computer Science (Harvard University via edX)
• Learning How to Learn (McMaster University via Coursera)
• The Science of Well-Being (Yale University via Coursera)

These courses cover some of the most essential skills and knowledge for modern developers. Machine learning and AI are two of the hottest areas in tech right now, powering everything from facial recognition to language translation to self-driving cars. The highly-rated courses from Stanford and Deeplearning.ai provide a solid foundation in these critical fields. Meanwhile, the Python, computer science, and learning techniques courses offer valuable lessons for programmers of all levels.

Diving deeper into the data, we can see that the MOOC landscape is dominated by a few major platforms. Coursera has the most courses in the top 250 with 100, followed by edX (78 courses) and FutureLearn (40). But there are other key players like Complexity Explorer, Kadenze, and independent course providers represented in the ranking as well.

Each platform offers something unique for learners. I‘m a big fan of Coursera‘s guided projects, which allow you to get hands-on coding practice right in your browser. EdX has a fantastic selection of more academic computer science courses from top universities like MIT and Harvard. And Udacity is known for their Nanodegree programs, which provide job-ready skills and credentials.

Another interesting lens we can use to examine this dataset is geography. Where in the world are the best free online courses being created? Perhaps unsurprisingly, the United States dominates the list with 102 courses, followed by the United Kingdom with 27. But the ranking includes courses from 26 different countries in total.

Here are some of the top countries along with their number of courses in the top 250:

Country	Number of Courses
United States	102
United Kingdom	27
India	12
China	6
Australia	5
Canada	5
France	5
Germany	5
Switzerland	4

It‘s wonderful to see such strong representation from countries around the globe. There are exceptional courses emerging from every continent.

A few individual institutions are responsible for a large number of the top courses:

• University of Pennsylvania (9 courses)
• University of Sheffield (9 courses)
• Hong Kong University of Science and Technology (HKUST) (9 courses)
• Massachusetts Institute of Technology (MIT) (8 courses)
• University of Leeds (8 courses)
• Universitat Politècnica de València (8 courses)
• University of Maryland (7 courses)
• Stanford University (7 courses)

Having taken courses from several of these universities myself, I can attest to their consistently high quality. The fact that such renowned institutions are embracing MOOCs and making their courses available for free is a huge benefit to learners everywhere.

Beyond the prestige of the institutions, however, it‘s the individual instructors that truly make these courses special. Having engaging, passionate teachers can make all the difference, especially in an online learning environment. Some of the most highly-rated MOOC instructors include:

• Barbara Oakley (McMaster University), who teaches the #1 ranked course "Learning How to Learn" and "Mindshift"
• Andrew Ng (Stanford University), who teaches several landmark AI and machine learning courses
• Scott Page (University of Michigan), who teaches "Model Thinking" and "Understanding Complexity"
• Jeff Ullman (Stanford University), who teaches courses on automata theory, databases, and mining massive datasets

As an experienced developer, I can‘t stress enough how valuable it is to learn from instructors of this caliber. MOOCs allow you to gain knowledge directly from some of the foremost experts in computer science and software engineering – an opportunity that would be impossible for most of us without this online format.

So what kind of real-world impact are these free online courses having? The short answer is: a massive one. In my work as a developer and participation in various tech communities, I regularly meet people who have used MOOCs to launch new careers, earn promotions, and build exciting projects. Here are a few examples:

• Sami, a stay-at-home mother in Egypt, took the "Python for Everybody" course and several other programming MOOCs. She is now working as a backend engineer and supporting her family.
• Toshiki, a university student in Japan, took the "Machine Learning" course and used his new skills to win a Kaggle competition on traffic forecasting.
• Marie-Claire, a business analyst in France, took courses in data science and programming from Johns Hopkins University and transitioned into a data scientist role at her company.

I‘ve personally used MOOCs to pick up new programming languages, refresh my math skills, and stay on top of emerging technologies like blockchain and cloud computing. In the fast-moving world of software development, we all need to be continuous learners. MOOCs are an indispensable resource.

Looking ahead, all the data points to a bright future for free online courses and the MOOC industry overall. Despite some early growing pains and hype cycles, MOOCs are now firmly established as a core part of the 21st century educational ecosystem. The combined market value of the major MOOC providers is nearly $10 billion and growing quickly [2].

One of the biggest shifts we‘re seeing is a move towards more recognized credentials, especially online degrees and micro-credentials. Enrollment in MOOC-based degrees has surged 170% in the last year alone [3]. Coursera alone now offers 27 degrees from universities like the University of Illinois, Imperial College London, and the University of Michigan [4]. These programs give learners the opportunity to earn valuable and career-boosting credentials from top institutions for a fraction of the normal cost.

We‘re also seeing a proliferation of smaller micro-credentials, like Coursera‘s Specializations and edX‘s Professional Certificate programs. These are designed to teach specific job skills in areas like data science, UX design, project management, and cloud computing. Industry leaders like Google, IBM, and Amazon Web Services are all investing heavily in developing their own MOOCs and micro-credentials. As a hiring manager, I increasingly look for these kinds of focused, practical learning experiences in potential candidates.

Another key trend is the growth of MOOCs in the developing world and in new languages. While the United States and other Western countries were the early adopters of MOOCs, recent years have seen an explosion of courses from rising economies and smaller countries. An analysis by Class Central found that the number of new courses offered in a language other than English has surpassed the number of courses in English [5]. There are now courses in over 100 languages on MOOC platforms, and this linguistic diversity will only increase going forward.

Finally, I want to close with some tips for any developers or aspiring techies looking to get the most out of MOOCs. As someone who has taken dozens of courses over the years, here are my biggest pieces of advice:

1. Code along with the instructor and build your own projects. Most programming courses include exercises and assignments, but go beyond these. Tinker with the code, extend the ideas, and create a portfolio you can show off.

2. Supplement the course with your own learning. MOOCs are a great starting point but to really deepen your knowledge, read books and blog posts related to the course topics, listen to podcasts, and join developer communities.

3. Become a mentor and share your knowledge with others. The best way to solidify your understanding is to teach. Look for opportunities to tutor, write articles, and contribute to open source projects.

4. Focus on learning the underlying concepts, not just the tools and technologies. Languages and frameworks change all the time, but if you master the fundamentals you‘ll have a much easier time adapting.

5. Have fun! Learning should be a joy, not a chore. Pick courses and projects that excite you and don‘t be afraid to explore unexpected areas. Some of my best learning experiences have come from courses I took on a whim.

I hope this deep dive into the world of free online courses has inspired you to start learning something new. The 250 courses featured in this ranking really are the best of the best, and they barely scratch the surface of what‘s out there. MOOCs have already transformed millions of lives around the globe and their impact will only continue to grow. As a developer in 2021, there‘s never been a better time to take advantage of these amazing resources. So what are you waiting for? Go sign up for a course and start expanding your mind today!