Khan Academy, a not-for-profit, offers a free world-class education for anyone, anywhere.

With a library of over 2,700 videos covering everything from arithmetic to physics, finance, and history and 259 practice exercises, Khan Academy is on a mission to help you learn what you want, when you want, at your own pace.

A free world-class education for anyone, anywhere
The Khan Academy is a not-for-profit with the goal of changing education for the better by providing a free world-class education to anyone anywhere.
All of the site's resources are available to anyone. It doesn't matter if you are a student, teacher, home-schooler, principal, adult returning to the classroom after 20 years, or a friendly alien just trying to get a leg up in earthly biology. The Khan Academy's materials and resources are available to you completely free of charge.

How it works for students
Students can make use of our extensive video library, practice exercises, and assessments from any computer with access to the web.
1. Complete custom self-paced learning tool
2. A dynamic system for getting help
3. A custom profile, points, and badges to measure progress

Coaches, parents, and teachers
Coaches, parents, and teachers have unprecedented visibility into what their students are learning and doing on the Khan Academy.
Visit http://www.khanacademy.org/ for more information.