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Khan Academy

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Khan Academy is an educational resource developed by an eponymous private nonprofit headed by educational entrepreneur Salman Khan. The resource includes:

  • A large number of videos prepared by Salman Khan.
  • A system of practice exercises available in some topics, linked to the videos. Practice exercises are available only for mathematics as of the time of writing this (November 2013).

Key takeaway

As a general rule, Khan Academy is unlikely to be the best thing for you to use. The majority of people who use Khan Academy do so because of the name recognition and the fact that it's free. If you care about the quality of your learning, you can do better. But the "better" resources vary by subject. Use our subject-specific learning recommendations to identify your best options. For instance, if you're interested in learning single-variable calculus, check out our single-variable calculus learning recommendations.

Video attributes

Attribute Value
Length of videos Typical videos are 5-12 minutes long, though there are some videos that are as long as 20 minutes.
Lecturer shown? No, voice-over
Format of presentation Electronically recorded writing on a tablet (Camtasia software)
Subtitles and closed captioning? Available for most videos in English. Available for some videos in other languages.
Voice translations? Available for a few videos in other languages.
Subjects covered? Wide range of subjects. Most comprehensive coverage is of mathematics.
Price Free


  • The videos cover practically all topics, and therefore one can reliably turn to Khan Academy when wanting to learn a topic.
  • The practice system is quite comprehensive and likely to improve, and the linking of the videos and the practice system makes for a better experience.


  • The presenter (Salman Khan) is not deeply knowledgeable about many of the subjects he presents videos on. This lack of knowledge shows in the choice of material presented and language used, and can be a hindrance to deep conceptual learning.
  • Many of the videos have poor handwriting and bad presentation, making them hard to follow.

Reviews from educators and teachers

Vipul Naik (COI disclosure: Naik is one of the co-authors of this wiki page and this wiki) wrote the following on Math StackExchange:

I find that the impressiveness of a Khan Academy video for me is negatively related to how much I know of the subject. As a math graduate student and calculus teacher, I find Khan's math/calculus videos the least impressive of the lot, his physics/chemistry/biology videos mildly impressive, and his history videos the most impressive.

What this suggests to me is that the Khan Academy is lacking in depth and clarity of presentation, as well as in addressing the subtleties and key issues that would be necessary to impress a person with some knowledge of the subject. Watching the Khan Academy is roughly akin to having a smart kid in your class (who is learning the subject along with you) explain to you what he/she has understood of the subject. It is not really comparable to how an expert teacher would convey the material.

This may not be completely a minus, because the lack of polish and the chumminess of the videos might itself be an endearing factor that makes people more comfortable with the videos. It also makes it easier to scale up and make a larger quantity of videos. Also, the low intensity of the videos makes it easy for a person to watch them when tired and distracted without missing out on too much.

Here are some examples of sloppiness:

(i) In the calculus videos, when I viewed them, the graphs were drawn very shakily, extremely hard to understand, and not well labeled. (ii) In a video on classical mechanics, there were some inaccurate statements about normal force, describing it as a reaction to gravitational force in the action-reaction sense (this was fixed later, I think). These weren't merely careless errors in speaking, but reflected a deeper lack of understanding. (iii) The examples and symbol choices are often confusing.

If you are recommending watching Khan Academy videos, I suggest you add the caveat that they should not expect a lot more (in terms of accuracy and quality of explanation) than they would expect learning from their colleagues.

Two mathematicians created a video critique of a (since removed) video on the Khan Academy about multiplication of negative numbers. The video critique was described on EdWeek. The article begins as follows:

In previous posts, I have summed up my position on Khan Academy as follows: Khan Academy teaches only one part of mathematics—procedures—and that isn't the most important part. Writing about mathematics, developing a disposition for mathematical thinking, demonstrating a conceptual understanding of mathematical topics are all more important than procedures. That said, procedures are still important, and Khan Academy provides one venue where students can learn them. In the end, I think every young person should have an account there. Even if only one in a thousand or ten thousand benefit, that would be a terrific outcome. (I pretty much said that verbatim in Shrewsbury on Tuesday in my flipped workshop. Ask Derek.) (There is a response from Khan in Updates at the bottom)

Dr. Keith Devlin offered a mixed review of Khan Academy in an article for The Huffington Post.

Reviews from student users

All reviews that appear here are either personally solicited for the wiki or are verified to be from people who write high-quality reviews.