Each tool is hand-reviewed and tagged so you can find exactly what fits your subject, level, and budget — in seconds, not hours.
Subject
Level
Cost
Showing 36 resources
Complete, structured math curriculum from early grades through calculus, with practice problems that adapt to your level.
Best for: Building foundations and filling specific knowledge gaps
Exceptionally clear written notes for Algebra through Calculus III and Differential Equations, with full worked examples.
Best for: University-level calculus and reference during problem sets
Visually stunning videos that build deep geometric intuition for calculus, linear algebra, and more.
Best for: Understanding the 'why' behind formulas you already use
Powerful free graphing tool to visualize functions, transformations, and relationships instantly.
Best for: Exploring how equations behave and checking your work
Interactive courses that teach math through guided problem-solving rather than lectures.
Best for: Active learners who want to think, not just watch
Full university courses including lecture notes, problem sets, and exams from MIT faculty.
Best for: Ambitious students ready for rigorous, university-level depth
Clear, concept-first tutorials covering high school and introductory physics with interactive checks.
Best for: Building solid conceptual foundations before the math
A vast concept map linking every physics topic, ideal for seeing how ideas connect across the field.
Best for: Quick reference and understanding relationships between topics
Structured video lessons with practice covering mechanics through modern physics.
Best for: Step-by-step learning with built-in practice
Free interactive simulations from the University of Colorado that let you experiment with physical systems.
Best for: Visualizing abstract concepts like fields, waves, and circuits
Walter Lewin's legendary lecture series with demonstrations that make mechanics unforgettable.
Best for: University-level mechanics with world-class teaching
Comprehensive coverage of general and organic chemistry with clear explanations and practice.
Best for: Structured learning from atoms to organic mechanisms
Thousands of clear worked-example videos across chemistry, physics, and math.
Best for: Working through problem types right before an exam
The world's largest free database of chemical molecules and their properties.
Best for: Looking up real compound data and structures
Virtual labs and simulations that let you run experiments and practice stoichiometry safely.
Best for: Practicing lab reasoning without a physical lab
A complete university general chemistry course with lectures, notes, and exams.
Best for: Deep, rigorous understanding of chemical principles
Friendly, memorable videos that demystify core biology concepts for high school and intro college.
Best for: Making tough topics like genetics finally click
Structured lessons covering cells, genetics, evolution, ecology, and human biology.
Best for: Comprehensive, organized coverage with practice
Fast-paced, engaging overviews ideal for a first pass or a quick refresher on a unit.
Best for: Getting the big picture before diving into detail
Interactive explorations of genetics, cells, and biotechnology from the University of Utah.
Best for: Visual, hands-on understanding of molecular biology
A full introductory biology course taught by leading MIT researchers.
Best for: Rigorous foundations for future life-science students
Harvard's famous introduction to computer science — rigorous, well-produced, and genuinely transformative.
Best for: Building real CS foundations, not just syntax
Thousands of hours of interactive coding curriculum with hands-on projects and certifications.
Best for: Learning web development by building projects
A complete, project-based full-stack web development curriculum used by self-taught developers.
Best for: A structured path from zero to employable web developer
Interactive lessons that let you write code directly in the browser with instant feedback.
Best for: Beginners who want guided, bite-sized practice
The standard platform for practicing algorithm and data-structure problems for interviews.
Best for: Preparing for technical interviews and competitions
The definitive free guide to writing, grammar, and citation styles (MLA, APA, Chicago) used by universities everywhere.
Best for: Citations, formatting, and grammar reference
Highlights complex sentences and passive voice so you can write with greater clarity.
Best for: Tightening prose and improving readability
Concise, expert guides on building arguments, thesis statements, and academic essay structure.
Best for: Learning to construct a real academic argument
Real-time grammar and style assistant that catches errors and suggests improvements as you write.
Best for: Catching mistakes in final drafts
Free reference manager that collects, organizes, and cites your research sources automatically.
Best for: Managing sources for research papers
The gold-standard spaced-repetition flashcard app that schedules reviews exactly when you're about to forget.
Best for: Long-term memorization of facts, vocabulary, and formulas
The most popular online course ever — a science-backed guide to studying effectively.
Best for: Understanding how your brain actually learns
Flexible workspace for organizing notes, tasks, and study schedules in one place.
Best for: Building a personal study and planning system
A clean, browser-based Pomodoro timer to structure focused work and breaks.
Best for: Beating procrastination and sustaining focus
Create and study flashcard sets with multiple practice modes and a huge shared library.
Best for: Quick vocabulary and definition practice