All Calculators
Pick a material or project. Each calculator shows the formula, an example and common mistakes.
Gamified Learning Cards: Japanese, IELTS, Python, Excel
Level cards, spaced repetition and XP/streaks for Japanese kana/N5/N4, IELTS, Spanish, Python, Git, Excel and Word/PPT.
免费 · FreeGamified Kana: Hiragana & Katakana Cards
Learn kana with level cards and spaced repetition: 92 hiragana/katakana cards, daily plans and gamified progress.
免费 · FreeJapanese N5 Kanji: Gamified 60-Card Deck
60 N5 kanji as level cards with 1/3/7/14/30/60/120-day review and on/kun readings.
免费 · FreeJapanese N4 Kanji: Gamified 60-Card Deck
60 N4 kanji as level cards that build on N5, with spaced review and on/kun readings.
免费 · FreeJapanese N4 Vocabulary: Gamified 60-Card Deck
60 high-frequency N4 words as level cards with kana, collocations and spaced review.
免费 · FreeJapanese N4 Grammar: Gamified 40-Pattern Deck
40 core N4 grammar patterns as level cards with connections, examples and spaced review.
免费 · FreeIELTS Core Words: Gamified 60-Card Deck
60 high-frequency IELTS academic words as level cards with Chinese meanings, examples and spaced review.
免费 · FreeSpanish Visual Vocabulary: Gamified 483-Card Deck
52 everyday themes, 483 Spanish words, level cards and spaced repetition with Chinese meanings and English hints.
免费 · FreePython Syntax: Gamified 60-Card Deck
60 Python syntax and built-in cards: guess the output, reveal, then review on a forgetting curve.
免费 · FreeGit Commands: Gamified 60-Card Deck
60 Git command and concept cards covering commits, branches, undo and recovery, with spaced review.
免费 · FreeExcel Functions: 1060 Gamified Cards
1060 Excel cards: 60 function basics plus 1000 range/constant formula-output questions, in 53 levels with spaced repetition.
免费 · FreeWord/PPT Shortcuts: Gamified 60-Card Deck
60 Word and PowerPoint shortcut cards covering formatting, alignment, slideshow and presenting, with spaced review.
免费 · FreeFrench Visual Vocabulary: Gamified 525-Card Deck
52 everyday themes, 525 French words, level cards and spaced repetition with Chinese meanings and English hints.
免费 · FreeEnglish Visual Vocabulary: Gamified 525-Card Deck
52 everyday themes, 525 English words, level cards and spaced repetition with Chinese meanings and Spanish hints.
免费 · FreeMental Math: 1000 Gamified Add/Subtract/Multiply/Divide Cards
1000 two-digit addition/subtraction, times-table and exact-division cards in 50 levels, with spaced repetition.
免费 · FreeSQL Queries: 1000 Gamified SELECT Practice Cards
1000 SQL query cards covering SELECT, WHERE, JOIN, GROUP BY, HAVING and subqueries, in 50 levels with spaced repetition.
免费 · FreePython Output: 1000 Gamified Expression and Method Cards
1000 Python output cards covering arithmetic, strings, lists, dicts, comprehensions and built-ins, in 50 levels with spaced repetition.
免费 · FreeJavaScript Output: 1000 Gamified Expression and Array Cards
1000 JavaScript output cards covering arithmetic, strings, array methods, objects, JSON and logic, in 50 levels with spaced repetition.
免费 · FreeRegex Practice: 1000 Gamified Match and Replace Cards
1000 Python regex cards covering character classes, quantifiers, groups, anchors, search and substitution, in 50 levels with spaced repetition.
免费 · FreeEnglish Grammar: 1000 Gamified Fill-in-the-Blank Cards
1000 English grammar fill-ins covering tenses, agreement, plurals, comparatives, articles, prepositions and passive voice, in 50 levels with spaced repetition.
免费 · FreeEnglish-French-Spanish Vocabulary: 1050 Gamified Cards
1050 English-French and English-Spanish cards across 52 everyday themes, with level cards and spaced repetition.
免费 · FreePeriodic Table Data: 1000 Gamified Chemistry Cards
1000 chemistry cards covering symbols, atomic numbers, atomic masses, common ions and isotope neutrons, in 50 levels with spaced repetition.
免费 · FreeWorld Geography: 1000 Gamified Country and Capital Cards
1000 world geography cards covering countries, capitals, regions, currencies and ISO codes, in 50 levels with spaced repetition.
免费 · FreePhysics Formulas: 1000 Gamified Calculation Cards
1000 physics calculation cards covering speed, density, force, work, power, pressure, Ohm's law, electric power, energy and heat, in 50 levels with spaced repetition.
免费 · FreeGeometry Formulas: 1000 Gamified Shape Calculation Cards
1000 geometry cards covering area, perimeter, volume and surface area for plane and solid shapes, in 50 levels with spaced repetition.
免费 · FreeSpanish Verb Conjugation: 1000 Gamified Regular Verb Cards
1000 Spanish regular verb conjugation cards covering -ar/-er/-ir in present, preterite, imperfect, future and conditional, in 50 levels with spaced repetition.
免费 · FreeFrench Verb Conjugation: 1000 Gamified Regular Verb Cards
1000 French regular verb conjugation cards covering -er/-ir/-re in present, imperfect, future, conditional and passé composé, in 50 levels with spaced repetition.
免费 · Free