Khan Academy

Khan Academy is a nonprofit learning platform offering free video lessons and practice exercises across mathematics, science, humanities, and standardized test preparation. Founded in 2008, it serves students, educators, and lifelong learners worldwide, with content designed for self-paced study from elementary through college levels. The platform is used by individual learners for supplementary instruction and by teachers to support classroom instruction.

Khan Academy is completely free with no premium tier or subscription model. All video lessons, practice exercises, progress tracking, and learning resources are accessible at no cost to individual learners. Educators can create free classroom accounts to monitor student progress and assign content.