[2022] The 250 Most Popular Online Courses of All Time

The best way to choose a free Massive Open Online Course (MOOC) is to choose one that other people have taken and enjoyed.

Class Central has been maintaining a catalog of these MOOCs ever since they rose to popularity back in 2012. According to Class Central’s 2021 annual report on MOOCs, 220M students have taken at least one course and over 950+ universities have launched 19,400+ courses.

To help learners decide which course to take, Class Central publishes a number of different rankings, including the Best Online Courses of all time based on the tens of thousands of reviews written by Class Central users.

In this ranking, we take a different approach. Instead of ranking courses by reviews, we rank by the number of students who enrolled in the course. In some cases, the top reviewed courses are also the courses with the most enrollments. In other cases, courses with large enrollments only have average reviews. This suggests there are popular courses that Class Central’s reviews have missed.

If you are looking for free certificates, check out some of our compilations:

Most Popular Online Courses of All Time

Here’s a quick summary of 250 most popular free online courses of all time, based on the number of enrollments:

• Enrollments range from 160K to 4.5 million. There are 15 courses with over 1 million enrollments.
• Together, they account for over 104 million enrollments, with an average of 416K enrollments.
• Interestingly, almost 40% of the courses are in the field of Business and Humanities.
• Over 76K reviews have been written on Class Central with an average rating of 4.02.
• 227 courses are in English, 19 are in Spanish and rest of them are in French, Dutch, and Portuguese.
• All courses are free to audit. You may need to pay for a certificate.
• Combined, they represent thousands of hours of content.

Interest in MOOCs and online education has never been greater. If you’re looking for a new online course, take a look at these free courses that millions of students have already taken. Here are the 250 most popular online courses, sorted by number of enrollments:

• Machine Learning from Stanford University ★★★★★(378)
• The Science of Well-Being from Yale University ★★★★★(26)
• CS50’s Introduction to Computer Science from Harvard University ★★★★★(109)
• Learning How to Learn: Powerful mental tools to help you master tough subjects from University of California, San Diego ★★★★★(20,275)
• Programming for Everybody (Getting Started with Python) from University of Michigan ★★★★★(33,837)
• English for Career Development from University of Pennsylvania ★★★★☆(24)
• Introduction to Computer Science and Programming Using Python from Massachusetts Institute of Technology ★★★★☆(126)
• COVID-19 Contact Tracing from Johns Hopkins University ★★★★★(12)
• IELTS Academic Test Preparation from University of Queensland ★★★★★(4)
• TOEFL® Test Preparation: The Insider’s Guide from ETS ★★★★★(6)
• Successful Negotiation: Essential Strategies and Skills from University of Michigan ★★★★★(15)
• First Step Korean from Yonsei University ★★★★★(125)
• Financial Markets from Yale University ★★★★☆(36)
• Chinese for Beginners from Peking University ★★★★☆(59)
• Neural Networks and Deep Learning from deeplearning.ai ★★★★★(15)
• Technical Support Fundamentals from Google ★★★★☆(10)
• Algorithms, Part I from Princeton University ★★★★★(59)
• Analyzing and Visualizing Data with Excel from Microsoft ★★★★☆(13)
• Introduction to Psychology from Yale University ★★★★★(14)
• Speak English Professionally: In Person, Online & On the Phone from Georgia Institute of Technology ★★★★☆(7)
• Exploring English: Language and Culture from British Council ★★★★★(783)
• Introduction to Linux from Linux Foundation ★★★★☆(37)
• AI For Everyone from deeplearning.ai ★★★★★(6)
• English Grammar and Style from University of Queensland ★★★★☆(33)
• Basic English 1: Elementary from King’s College London ★★★★☆(7)
• Entrepreneurship in Emerging Economies from Harvard University ★★★★★(10)
• Data Science: R Basics from Harvard University ★★★★★(11)
• The Data Scientist’s Toolbox from Johns Hopkins University ★★★☆☆(166)
• HTML, CSS, and Javascript for Web Developers from Johns Hopkins University ★★★★★(21)
• Excel Skills for Business: Essentials from Macquarie University ★★★★☆(7)
• Stanford Introduction to Food and Health from Stanford University ★★★★☆(43)
• Introduction to Data Science in Python from University of Michigan ★★☆☆☆(46)
• Grammar and Punctuation from University of California, Irvine ★★★★☆(33)
• Bitcoin and Cryptocurrency Technologies from Princeton University ★★★★☆(27)
• English for the Workplace from British Council ★★★★★(1398)
• Foundations: Data, Data, Everywhere from Google ★★★★★(1)
• Google Cloud Fundamentals: Core Infrastructure from Google ★★★★☆(6)
• Fundamentals of Graphic Design from California Institute of the Arts ★★★★☆(20)
• Buddhism and Modern Psychology from Princeton University ★★★★★(29)
• Introduction to Philosophy from University of Edinburgh ★★★★☆(74)
• What is Data Science? from IBM ★★★★☆(4)
• Marketing in a Digital World from University of Illinois at Urbana-Champaign ★★★★★(225)
• The Science of Happiness from University of California, Berkeley ★★★★★(33)
• Basic Spanish 1: Getting Started from Universitat Politècnica de València ★★★★☆(365)
• Rhetoric: The Art of Persuasive Writing and Public Speaking from Harvard University ★★★★☆(5)
• Contract Law: From Trust to Promise to Contract from Harvard University ★★★★★(13)
• The Architectural Imagination from Harvard University ★★★★☆(12)
• Justice from Harvard University ★★★★★(49)
• Social Psychology from Wesleyan University ★★★★★(83)
• Crash Course on Python from Google
• Fundamentals of Neuroscience, Part 1: The Electrical Properties of the Neuron from Harvard University ★★★★★(20)
• Programming for Everybody (Getting Started with Python) from University of Michigan ★★★★★(1)
• Programming Foundations with JavaScript, HTML and CSS from Duke University ★★★★☆(12)
• Finanzas personales from Universidad Nacional Autónoma de México
• Python Basics for Data Science from IBM ★★☆☆☆(3)
• Introduction to HTML5 from University of Michigan ★★★★☆(48)
• Indigenous Canada from University of Alberta ★★★★☆(9)
• Child Nutrition and Cooking from Stanford University ★★★★☆(31)
• A Life of Happiness and Fulfillment from Indian School of Business ★★★★★(503)
• Introduction to Programming with MATLAB from Vanderbilt University ★★★★★(207)
• Algorithmic Toolbox from University of California, San Diego ★★★★☆(23)
• Primeros Auxilios Psicológicos (PAP) from Universitat Autònoma de Barcelona (Autonomous University of Barcelona) ★★★★★(1)
• Psychological First Aid from Johns Hopkins University ★★★★☆(48)
• Introduction to Negotiation: A Strategic Playbook for Becoming a Principled and Persuasive Negotiator from Yale University ★★★★★(13)
• Work Smarter, Not Harder: Time Management for Personal & Professional Productivity from University of California, Irvine ★★★★☆(42)
• Modern Art & Ideas from The Museum of Modern Art ★★★★★(5)
• Foundations of Project Management from Google ★☆☆☆☆(1)
• Introductory Human Physiology from Duke University ★★★★☆(29)
• Introduction to Psychology from University of Toronto ★★★★★(26)
• Introduction to Project Management from University of Adelaide ★★★★☆(6)
• Mindfulness for Wellbeing and Peak Performance from Monash University ★★★★★(210)
• Financial Engineering and Risk Management Part I from Columbia University ★★★★☆(13)
• Basic English 2: Pre-Intermediate from King’s College London ★★★★★(6)
• Mindshift: Break Through Obstacles to Learning and Discover Your Hidden Potential from McMaster University ★★★★★(6749)
• Contabilidad para no contadores from Universidad Nacional Autónoma de México
• Academic and Business Writing from University of California, Berkeley ★★★★☆(15)
• Étudier en France: French Intermediate course B1-B2 from École Polytechnique ★★★★★(4)
• Start Writing Fiction from The Open University ★★★★☆(20)
• Introduction to Mathematical Thinking from Stanford University ★★★★☆(52)
• HTML5 and CSS Fundamentals from World Wide Web Consortium (W3C) ★★★★☆(6)
• Initiating and Planning Projects from University of California, Irvine ★★★★☆(19)
• Statistics and R from Harvard University ★★★★☆(20)
• Game Theory from Stanford University ★★★★☆(34)
• Excel: Fundamentos y herramientas from Universitat Politècnica de València ★★★★★(499)
• Design Thinking for Innovation from University of Virginia ★★★★★(5)
• SQL for Data Science from University of California, Davis ★★★★☆(4)
• Competitive Strategy from Ludwig-Maximilians-Universität München ★★★★★(22)
• How to Write an Essay from University of California, Berkeley ★★★★☆(26)
• English for Business and Entrepreneurship from University of Pennsylvania ★★★★★(7)
• A Beginner’s Guide to Writing in English for University Study from University of Reading ★★★★☆(22)
• Machine Learning Foundations: A Case Study Approach from University of Washington ★★★★☆(40)
• Cryptography I from Stanford University ★★★★★(53)
• Introduction to Java Programming: Starting to code in Java from Universidad Carlos iii de Madrid ★★★★☆(7)
• Mechanical Ventilation for COVID-19 from Harvard University ★★★★★(24)
• Gestión de proyectos de desarrollo from IDB (Inter-American Development Bank) ★★★★☆(2)
• Learn to Speak Korean 1 from Yonsei University ★★★★★(12)
• English Composition I from Duke University ★★★☆☆(19)
• Conversational English Skills | 生活英语听说 from Tsinghua University ★★★★☆(12)
• Introduction to C++ from Microsoft ★★★★☆(7)
• The Science of Everyday Thinking from University of Queensland ★★★★★(48)
• Foundations of User Experience (UX) Design from Google
• Build Your First Android App (Project-Centered Course) from École Centrale Paris ★★★★☆(5)
• Mastering Data Analysis in Excel from Duke University ★★☆☆☆(26)
• Teaching English Online from Cambridge English Language Assessment ★★★★★(2)
• Introduction to Cyber Security from The Open University ★★★★☆(21)
• Principles of Biochemistry from Harvard University ★★★★★(13)
• Aprendiendo a aprender: Poderosas herramientas mentales con las que podrás dominar temas difíciles (Learning How to Learn) from University of California, San Diego ★★★★★(8)
• Using Python for Research from Harvard University ★★★★☆(12)
• Introduction to Marketing from University of Pennsylvania ★★★★☆(74)
• Python for Data Science from University of California, San Diego ★★★★☆(47)
• Data Science Math Skills from Duke University ★★★★☆(10)
• Python Basics from University of Michigan ★★★★☆(1)
• Marketing Analytics from University of Virginia ★★★★☆(12)
• Writing in the Sciences from Stanford University ★★★★★(12)
• Leaders of Learning from Harvard University ★★★★☆(19)
• Science of Exercise from University of Colorado Boulder ★★★★★(4)
• Introduction to Java Programming – Part 1 from The Hong Kong University of Science and Technology ★★★☆☆(6)
• Think Again I: How to Understand Arguments from Duke University ★★★★☆(11)
• Vital Signs: Understanding What the Body Is Telling Us from University of Pennsylvania ★★★★★(51)
• Introduction to Big Data from University of California, San Diego ★★★☆☆(35)
• Guitar for Beginners from Berklee College of Music ★★★★★(21)
• Introduction to TensorFlow for Artificial Intelligence, Machine Learning, and Deep Learning from deeplearning.ai ★★★★★(1)
• Artificial Intelligence (AI) from Columbia University ★★★★☆(12)
• Introduction to the Internet of Things and Embedded Systems from University of California, Irvine ★★★★☆(12)
• How to Succeed at: Interviews from The University of Sheffield ★★★★★(424)
• Positive Psychology from The University of North Carolina at Chapel Hill ★★★★☆(28)
• Fundamentals of Music Theory from University of Edinburgh ★★★★☆(23)
• Learn to Program: The Fundamentals from University of Toronto ★★★★★(109)
• Camino a la Excelencia en Gestión de Proyectos from Pontificia Universidad Católica de Chile
• The Strategy of Content Marketing from University of California, Davis ★★★★☆(8)
• Mathematics for Machine Learning: Linear Algebra from Imperial College London ★★★☆☆(8)
• Exploring English: Shakespeare from British Council ★★★★★(457)
• Understanding Language: Learning and Teaching from University of Southampton ★★★★☆(7)
• Fundamentos de Excel para Negocios from Universidad Austral ★★★★★(1)
• How to Succeed at: Writing Applications from The University of Sheffield ★★★★★(401)
• Italian Language and Culture: Beginner (2021-2022) from Wellesley College ★★★★☆(3)
• Medical Neuroscience from Duke University ★★★★★(46)
• Introduction to Dutch from University of Groningen ★★★★★(268)
• Aprender from Universidad Nacional Autónoma de México ★★★★★(106)
• Child Protection: Children’s Rights in Theory and Practice from Harvard University ★★★★★(4)
• An Introduction to Screenwriting from University of East Anglia ★★★★★(4)
• Supply Chain Fundamentals from Massachusetts Institute of Technology ★★★★★(14)
• Introduction to User Experience Design from Georgia Institute of Technology ★★★☆☆(3)
• Front-End Web UI Frameworks and Tools: Bootstrap 4 from The Hong Kong University of Science and Technology
• Probability – The Science of Uncertainty and Data from Massachusetts Institute of Technology ★★★★★(32)
• Basic Statistics from University of Amsterdam ★★★★☆(12)
• Introduction to Personal Branding from University of Virginia ★★★★☆(15)
• AWS Fundamentals: Going Cloud-Native from Amazon Web Services ★★★★☆(1)
• Algorithms, Part II from Princeton University ★★★★★(21)
• Learn to Program in Java from Microsoft ★★★★☆(5)
• Brand Management: Aligning Business, Brand and Behaviour from University of London International Programmes ★★★★★(2)
• Programming Basics from Indian Institute of Technology Bombay ★★★☆☆(18)
• Querying Data with Transact-SQL from Microsoft ★★★★☆(4)
• Introduction to Probability and Data with R from Duke University ★★★★☆(6)
• Álgebra básica from Universidad Nacional Autónoma de México
• Fundamentals of Project Planning and Management from University of Virginia ★★★★☆(28)
• Google Cloud Big Data and Machine Learning Fundamentals from Google Cloud ★★★☆☆(3)
• Understanding Research Methods from University of London International Programmes ★★★★☆(15)
• Robótica from Universidad Nacional Autónoma de México ★★☆☆☆(2)
• A Hands-on Introduction to Engineering Simulations from Cornell University ★★★★★(2)
• Customer Analytics from University of Pennsylvania ★★★☆☆(16)
• Food as Medicine from Monash University ★★★★★(114)
• Code Yourself! An Introduction to Programming from University of Edinburgh ★★★★☆(12)
• Introduction to Kubernetes from Linux Foundation
• Viral Marketing and How to Craft Contagious Content from University of Pennsylvania ★★★★☆(27)
• Becoming a Successful Leader (Inclusive Leadership Training)
• English in Early Childhood: Language Learning and Development from British Council ★★★★★(1292)
• Cameras, Exposure, and Photography from Michigan State University ★★★★☆(6)
• Nutrition and Health: Macronutrients and Overnutrition from Wageningen University ★★★★★(283)
• How Things Work: An Introduction to Physics from University of Virginia ★★★★★(28)
• Digital Skills: Digital Marketing from Accenture ★★★★☆(5)
• Python Programming: A Concise Introduction from Wesleyan University ★★★★☆(6)
• Understanding the Brain: The Neurobiology of Everyday Life from The University of Chicago ★★★★★(28)
• C++ For C Programmers, Part A from University of California, Santa Cruz ★★★☆☆(26)
• Cómo hacer una tesis from Universidad Nacional Autónoma de México ★★★★☆(1)
• Introduction to Google SEO from University of California, Davis ★★★★☆(5)
• Gestión Empresarial Exitosa para Pymes from Pontificia Universidad Católica de Chile
• Creative Problem Solving from University of Minnesota ★★★☆☆(19)
• Introduction to Data Analysis Using Excel from Rice University ★★★☆☆(2)
• Statistical Thinking for Data Science and Analytics from Columbia University ★★☆☆☆(19)
• Introduction to Classical Music from Yale University ★★★★★(26)
• Introduction to Engineering Mechanics from Georgia Institute of Technology ★★★★★(168)
• Inglés básico: conversacional y networking from Universidad Anáhuac ★★★★★(48)
• Introduction to Public Speaking from University of Washington ★★★★☆(14)
• Begin Programming: Build Your First Mobile Game from University of Reading ★★★★☆(8)
• Creative Writing: The Craft of Plot from Wesleyan University ★★★★☆(17)
• Computing in Python I: Fundamentals and Procedural Programming from Georgia Institute of Technology ★★★★★(203)
• Buddhism Through Its Scriptures from Harvard University ★★★★☆(6)
• De-Mystifying Mindfulness from Leiden University ★★★★★(92)
• Introduction to Marketing from The University of British Columbia ★★★★★(6)
• Tricky American English Pronunciation from University of California, Irvine ★★★★☆(15)
• Creative Thinking: Techniques and Tools for Success from Imperial College London ★★★★★(14)
• How to Learn Online
• Logical and Critical Thinking from University Of Auckland ★★★★★(14)
• Functional Programming Principles in Scala from École Polytechnique Fédérale de Lausanne ★★★★★(66)
• Greek and Roman Mythology from University of Pennsylvania ★★★★★(21)
• How to Write a Resume (Project-Centered Course) from State University of New York ★★★★☆(13)
• Nutrición y obesidad: control de sobrepeso from Universidad Nacional Autónoma de México ★★★★★(1)
• Forensic Psychology: Witness Investigation from The Open University ★★★★★(18)
• Positive Psychiatry and Mental Health from The University of Sydney ★★★★★(22)
• Management of Fashion and Luxury Companies from Università Bocconi ★★★★★(3)
• An Introduction to Interactive Programming in Python (Part 1) from Rice University ★★★★★(3311)
• Introducción a la programación en Python I: Aprendiendo a programar con Python from Pontificia Universidad Católica de Chile ★★★★★(2)
• Cybersecurity Fundamentals from Rochester Institute of Technology ★★★★★(24)
• Java for Android from Vanderbilt University ★☆☆☆☆(1)
• Introducción a Data Science: Programación Estadística con R from Universidad Nacional Autónoma de México ★★★★☆(2)
• Dog Emotion and Cognition from Duke University ★★★★☆(19)
• Divide and Conquer, Sorting and Searching, and Randomized Algorithms from Stanford University ★★★★★(67)
• Ser más creativos from Universidad Nacional Autónoma de México ★★★★☆(2)
• Introduction to Cybersecurity Tools & Cyber Attacks from IBM ★★★☆☆(2)
• Astronomy: Exploring Time and Space from University of Arizona ★★★★★(21)
• Introduction to Web Development from University of California, Davis ★★★★☆(3)
• Getting Started with AWS Machine Learning from Amazon Web Services ★★★★☆(12)
• Introduction to Logic from Stanford University ★★★☆☆(20)
• English for Journalism from University of Pennsylvania ★★★★☆(15)
• A Crash Course in Data Science from Johns Hopkins University ★★★★☆(24)
• Influencing People from University of Michigan ★★★★☆(7)
• Introdução à Ciência da Computação com Python Parte 1 from Universidade de São Paulo ★★★★★(1)
• Introduction to Biology – The Secret of Life from Massachusetts Institute of Technology ★★★★★(109)
• Computer Architecture from Princeton University ★★★★☆(6)
• Introduction to Electronics from Georgia Institute of Technology ★★★★☆(6)
• How To Create a Website in a Weekend! (Project-Centered Course) from State University of New York ★★★★☆(7)
• Aprendendo a aprender: ferramentas mentais poderosas para ajudá-lo a dominar assuntos difíceis (em Português) [Learning How to Learn] from University of California, San Diego ★★★★☆(5)
• Mind Control: Managing Your Mental Health During COVID-19 from University of Toronto ★★★★☆(10)
• Model Thinking from University of Michigan ★★★★★(66)
• Moral Foundations of Politics from Yale University ★★★★☆(15)
• Responsive Website Basics: Code with HTML, CSS, and JavaScript from University of London International Programmes ★★★★☆(26)
• Epidemiology: The Basic Science of Public Health from The University of North Carolina at Chapel Hill ★★★★☆(28)
• Competencias digitales. Herramientas de ofimática (Microsoft Word, Excel, Power Point) from Universitat Autònoma de Barcelona (Autonomous University of Barcelona) ★★★★★(3)
• Spanish Vocabulary: Meeting People from University of California, Davis ★★★☆☆(1)
• Introduction to the Biology of Cancer from Johns Hopkins University ★★★★☆(9)
• The Modern World, Part One: Global History from 1760 to 1910 from University of Virginia ★★★★★(25)
• Supply Chain Logistics from Rutgers University ★★★★☆(5)
• Introduction to Deep Learning from Higher School of Economics ★★★☆☆(3)
• Starting a Business 1: Vision and Opportunity from University of Leeds ★★★★★(84)
• Cybersecurity and Its Ten Domains from University System of Georgia ★★★☆☆(9)
• Bitcoin and Cryptocurrencies from University of California, Berkeley
• Business English: Networking from University of Washington ★★★★★(1)
• Management and Leadership: Growing as a Manager from The Open University ★★★★★(5)
• Human Anatomy: Musculoskeletal Cases from Harvard University ★★★★★(8)
• Programming Fundamentals from Duke University
• The Addicted Brain from Emory University ★★★★☆(24)
• Communication and Interpersonal Skills at Work from University of Leeds ★★★★☆(6)
• English for Academic Study from Coventry University ★★★★★(2)
• Database Management Essentials from University of Colorado System ★★★★☆(5)
• Blockchain Basics from University at Buffalo ★★☆☆☆(1)
• Perfect Tenses and Modals from University of California, Irvine ★★★★★(6)
• Introduction to Social Media Marketing from Facebook
• Preparing to Manage Human Resources from University of Minnesota ★★★★★(116)
• Miracles of Human Language: An Introduction to Linguistics from Leiden University ★★★★★(80)

In addition to this, Class Central also publishes the 100 Most Popular Courses of all time for each year. For these rankings, we only look at courses launched in that year.