A real curriculum, delivered inside a browser tab

Free education, for anyone, anywhere. That sentence has been the stated purpose of Khan Academy for the better part of two decades, and the organisation behind it is a non-profit rather than a company with a subscription to sell. The whole thing began with one person recording lessons for a cousin who needed help with mathematics. It now holds more than a hundred and eighty million registered learners, covers the ground from preschool to the early years of university, and speaks more than fifty languages. Learners and teachers pay nothing, and work on the material was still going on as of September 2026.

From counting to advanced placement

Mathematics is the traditional strength, and the ladder is unusually complete: number sense for the very young, arithmetic from the primary years, then algebra, geometry and on to calculus and linear algebra. Every topic arrives with an explanatory video, an interactive exercise and hints that appear one step at a time rather than all at once. Beyond mathematics the catalogue includes science, grammar, history and civics, economics and computer programming, plus the kind of life skill that schools rarely timetable, such as financial literacy and career exploration. On the examination side there is preparation for the SAT and for several advanced placement subjects, with practice questions and pre-exam drills open at no cost.

Practice decides whether something was learned

The learning model is built around mastery rather than completion. A video can be watched in a distracted minute, so a skill only counts once an exercise has demonstrated it, and a wrong answer produces a hint aimed at the specific mistake instead of a page of explanation. Progress is broken into individual skill points, which turns a vague sense of getting better into something countable. The system also schedules material back for review, so that what was learned in March has not vanished by June, and a progress bar next to each skill keeps the distance to the goal visible. For someone studying alone this rhythm is unusually kind, and for a parent it answers the question that matters most, which is what the child can actually do.

Exam preparation with a structure

The free examination material is where a great many users first arrive. The SAT course is built in partnership with the organisation that sets the test, and the reading and writing half is broken into challenge units by question type, so a weak area can be attacked directly instead of by working through another full paper. Advanced placement courses cover calculus, physics, statistics and more, each with an explanation of the concepts being examined and practice that imitates the real paper. For anyone preparing without a tutor, the value of that material is considerable.

A cockpit for parents and one for teachers

A parent account can be linked to a child, which makes the record of what was studied, and where the child got stuck, readable at a glance. The teacher dashboard goes further: exercises can be assigned, the mastery of a whole class becomes visible in one view, and students at different levels can be guided separately rather than all at the pace of the middle. For younger children there is a separate application that teaches numerals and letter sounds through games and stories, and downloaded content keeps working without a connection, with no advertising in the way. An AI tutoring assistant is also part of the service, and it is designed to lead a stuck learner through the reasoning step by step instead of simply printing the answer. The basic functions cost nothing; deeper use can be paired with a paid subscription.

Why it has stayed free

As a non-profit the organisation runs on donations and partners, which is what allows the site and the courses to carry no advertising and to charge neither students nor their parents. The videos are generally short, a few minutes to make one concept clear, so a fragmented day still has room for a lesson. Translation into further languages continues, which means a learner outside the English-speaking world can still find a complete course rather than a sample. Whether the aim is to repair a shaky foundation, to run ahead of a class, or simply to sit beside a child and learn together, an account is enough to begin.