4.7
Interactive STEM courses with a daily lesson and a Premium wall.
Free practice for the subjects your course assumed you already knew.
Best for filling gaps in maths, science, and economics
Reviewed 16 September 2026 · Prices checked the same day
4.8
210K reviews
Khan Academy is free, non-profit, and still the best gap-filler when a lecture jumped a step. Mastery paths, videos, and exercises cover school through early undergraduate. Khanmigo is the optional paid tutor.
It will not replace your course. It will replace a panicky reread of a chapter you never understood the first time.
Pricing
free
Optional Khanmigo tutor subscription
Free version
Core practice and videos are free
Platforms
Web · iOS · Android
Use it the week you realised you missed a prerequisite. Then go back to your own cards.
Checked 2026-09-16
| Model | Free |
|---|---|
| What free actually includes | Core practice and videos are free |
| Cheapest paid tier | Optional Khanmigo tutor subscription |
| Student pricing | None published |
Links from StudyApps include ref=studyapps.
Core practice and videos are free Checked 16 September 2026.
Cheapest paid plan: Optional Khanmigo tutor subscription. Prices checked 16 September 2026.
Filling gaps in maths, science, and economics
Stops being enough at advanced undergrad
Interactive STEM courses with a daily lesson and a Premium wall.
Daily language streaks, with Super removing the energy gate.
The graphing calculator that should replace the one in your bag.