Free Education & Reference Software

Anki is arguably the most powerful free learning tool available. It implements a spaced-repetition algorithm (based on the SM-2 algorithm developed by Piotr Woźniak) that schedules flashcard reviews at optimal intervals to maximize long-term retention. Widely used by medical and law students, language learners, and anyone who needs to memorize large bodies of information. Supports text, audio, images, and video in cards. Sync across devices is free via AnkiWeb.

GeoGebra is an interactive mathematics application used in classrooms worldwide. It integrates algebra, geometry, calculus, statistics, and 3D geometry in a single environment. Students and teachers can construct dynamic figures, plot functions, work with matrices, and explore mathematical concepts interactively. Available as a web app and as a desktop download.

GNU Octave is a free, open-source numerical computing environment designed to be largely compatible with MATLAB. It provides a high-level language for numerical analysis, linear algebra, signal processing, and data visualization. Used extensively in engineering and science courses as a free alternative to the costly MATLAB license.

SageMath is a free, open-source mathematics software system that builds on Python and integrates over 90 open-source mathematical packages. It covers algebra, combinatorics, numerical mathematics, calculus, and much more. Offers a Jupyter notebook interface for interactive computation. Used in university mathematics and research.

Stellarium is a free, open-source planetarium for your desktop. It renders a photorealistic 3D sky from any point on Earth at any time, showing stars, constellations, nebulae, planets, the Moon, the Sun, and satellites in real time or simulated time. Includes multiple catalog layers, constellation artwork from different cultures, and a telescope control plugin. Used in schools, planetariums, and by amateur astronomers worldwide.

Tux Typing is a fun, kid-friendly free typing tutor for children. Linux's penguin mascot Tux stars in mini-games that teach letter recognition and typing speed through engaging gameplay rather than repetitive drills. Available for Windows, macOS, and Linux.

KTouch is a touch-typing tutor from the KDE project. It provides structured lessons that teach proper finger placement and gradually build speed and accuracy. Supports multiple keyboard layouts and languages, tracks progress over time, and allows custom lessons. Available for Windows, macOS, and Linux.

Marble is a KDE virtual globe and world atlas. It displays the Earth in various projections — satellite imagery, flat map, physical relief, OpenStreetMap — and includes downloadable offline map packages. Marble is a good introduction to the geography of the world and includes routing and GPS track visualization.

Mentioned also in the Productivity section, Zotero deserves a note here for its educational applications. For students writing research papers, Zotero automates the most tedious parts of the process: capturing sources, organizing references, and generating citations and bibliographies in APA, MLA, Chicago, and hundreds of other styles. Free, cross-platform, and open source.