About Us


CK-12 Foundation is a non-profit organization dedicated to increasing access to high quality educational materials for K-12 students all over the world. We offer free high-quality, standards-aligned, open content in the STEM subjects. By providing these free resources, CK-12 is working toward educational equity for all.

What We Provide

An integrated set of tools for learning: digital textbooks, concept-based learning, SAT prep, and interactive Algebra curriculum (with additional math and science subjects in progress). All products can be customized to match the needs of the student, educator, or school.


The FlexBook System is an online platform for assembling, authoring, and distributing interactive, multi-modal content

in the form of FlexBooks and concepts.

  • FlexBooks – Our books are fully customizable and can easily be kept up-to-date. You can rearrange the chapters or even add, remove, and edit content.
  • Concepts – These bite-sized lessons can be added to a FlexBook or assigned directly to students for independent learning.
  • Interactive Learning Objects – Videos and multimedia simulations bring learning to life.
  • Exercises – Enable students to track their progress with instant feedback.
  • Teaching Materials – Get assessments, answer keys and ideas for differentiated instruction.

FlexMath is a web-based interactive Algebra I curriculum that provides daily lessons and real-time feedback to help raise student achievement.



INeedAPencil provides free online SAT preparation with practice questions and an adaptive SAT score predictor.



studyHELP is a peer-to-peer social learning (Facebook) application allowing students to ask questions whenever the need answers, form study groups, and explore a rich library of K-12 content.



Braingenie builds deep mastery and sharpens problem-solving skills through the most comprehensive K-12 math and science practice content.