Khan Academy — Math
Free, self-paced math courses from basic arithmetic through multivariable calculus, linear algebra, and differential equations.
freemath
Public VaultMathematics
Math From Zero to Calc
Algebra to multivariable calculus — free courses, video series, graphing tools, and step-by-step solvers that actually explain the why.
3Blue1Brown
Visual, intuitive explanations of calculus, linear algebra, neural networks, and more. Watch the "Essence of Calculus" series first.
mathcalculus
Paul's Online Math Notes
Legendary free notes for Algebra, Calc I, Calc II, Calc III, and Differential Equations. Often clearer than the assigned textbook.
mathcalculus
Desmos Graphing Calculator
The best free graphing calculator on the web. Visualize functions, explore transformations, and check your work instantly.
freemath
Wolfram Alpha
Step-by-step solutions to math problems — not just the answer but the full working. Essential for checking work and learning methods.
studymath
Professor Leonard (YouTube)
Full university-level math lecture series on YouTube: Precalculus, Calc I/II/III, Statistics, Differential Equations. Best free professor online.
mathcalculus
MIT OCW — Mathematics
MIT's full math course catalog with lecture notes, assignments, and exams. Especially strong for linear algebra and real analysis.
freemath
PatrickJMT
Thousands of short, focused math tutorial videos organized by topic. Perfect for quickly understanding a concept before a test.
studymath