Khan Academy

Khan Academy is a free, nonprofit learning site covering everything from early math to college-level science, economics and test prep. It pairs short video lessons with interactive practice exercises, so you can learn at your own pace — whether you're a student, a parent or just curious.

Key Features

• Free forever: every course and lesson is completely free.
• Video lessons: short, clear videos explain each concept.
• Practice exercises: interactive problems with instant feedback.
• Personalized learning: the site adapts to your level and progress.
• Test prep: practice for the SAT, LSAT and other standardized tests.
• Every grade and subject: math, science, history, economics and more.
• Teacher tools: educators can assign lessons and track student progress.

Pricing

• Free: 100% free for everyone — no subscription, ever.
• Supported by donations: Khan Academy is a nonprofit funded by donors.

Getting Started

Go to khanacademy.org and create a free account. Choose a subject or grade level and start with a video lesson followed by practice — you can even try many courses without signing in.