CK-12 Study Guides

Produced by the CK-12 Foundation, a non-profit organisation, the study guides are organised by subject and topic, covering areas including algebra, geometry, calculus, biology, chemistry, physics, earth science, and English language arts. Each guide condenses material into summaries, definitions, worked examples, diagrams, and practice questions, and is aligned with curriculum standards commonly used in the United States, although the content is also applicable to learners following other syllabuses.

The guides are available to view online through a web browser and can be downloaded as PDF documents for offline use or printing. The study guides form part of the wider CK-12 platform, which includes interactive textbooks (FlexBooks), adaptive practice exercises, simulations, and video lessons.

Teachers can assign guides to classes, share links with students, and incorporate them into lesson plans, while students and self-directed learners can use them for revision, homework support, and exam preparation. Access to the study guides is free and does not require a paid subscription, although registering for a CK-12 account allows users to save progress, join classes, and track activity across the platform.