Free online learning tools

Looks up English and Hindi words with meanings and examples.

Interactive essay that explores a simulated car design at different levels of abstraction.

Insert, delete and search a BST or AVL tree and watch each rotation animate.

Explains and demonstrates the Caesar cipher with a working encoder.

Emulates an Enigma machine and shows how the wiring changes each letter.

Quran reader and free API with many editions and translations.

Shows daily prayer times and Hijri dates for a city, with an adhan player.

Large guitar chord library with finger placements and audio samples.

Arabic learning tools including a transliteration helper and word tools.

Builds printable crosswords from words and clues.

Online reader of Panini grammar rules with commentary and search.

Free American Sign Language lessons by Dr Bill Vicars.

Team quiz games for the classroom built from your own questions.

Identifies a pasted character and shows its Unicode details.

Converts many Unix timestamps to readable dates at once.

Reads the Bhagavad Gita verse by verse with translations and commentary.

Generates bibliographies and works cited lists in MLA, APA and Chicago styles.

Free citation generator supporting APA, MLA, Harvard and thousands of other styles.

Searches and reads the Bible in many translations side by side.

Shows Hebrew and Greek Bible text aligned word by word with English.

Edit .bib files in a form view for BibTeX and BibLaTeX.

Large full screen countdown timer for classrooms and meetings.

Bible study tool with search, concordance and original language lexicons.

Shows the Braille alphabet and numbers with interactive practice.