Is Khan Academy enough to learn maths?

Let us start with the concession, because it is real. Khan Academy is one of the best things on the internet. The explanations are patient, the practice sets are solid, the coverage runs from counting to multivariable calculus, and a nonprofit gives it all away. If someone has the discipline to work through it end to end, they will learn real mathematics. Nothing below argues otherwise.

But most adults who start a maths course online do not finish it, and the reasons are rarely about lesson quality. They are about three structural jobs that lessons alone cannot do.

What Khan Academy is still the best free option for

Being concrete about the concession before picking at it. If you want a second explanation of something you have half understood, Khan Academy is the first place to look and it costs nothing. If you are a school student following a syllabus with a teacher who sets the order and marks the work, the first two gaps below are already being covered by a human, and Khan is genuinely enough. If you need one topic by next week, its unit on that topic is as good as anything paid. And for anyone whose binding constraint is money rather than time, a nonprofit giving away arithmetic through multivariable calculus is not a compromise option, it is the correct answer, and no amount of product differentiation on our side changes that.

1. Diagnosis: which of 1,000 concepts are you missing?

Khan Academy asks you to choose a course, and within one it lets you test out of units. What it cannot tell you is where, across the whole of mathematics, your knowledge actually ends. An adult with shaky fractions who enrols in Algebra 1 will meet that gap on week two, experience it as being bad at algebra, and quit. The gap was diagnosable. Nothing in a course-shaped product is built to diagnose it, because the course was chosen before the question was asked.

2. Sequencing: a playlist is not a map

Courses sequence material the way school terms need it delivered: linearly, one cohort, one pace. But mathematical knowledge is a dependency graph, and your gaps do not respect course boundaries. The efficient route for you might take three sections of pre-algebra, skip half of geometry, and rejoin at trigonometry. No playlist can express that route; a prerequisite map can, and it is why Consiliae is built as one.

3. Retention: finishing a unit is not keeping it

The third gap is the quiet one. Memory for mathematics decays on a schedule, and the only known fix is reviewing material at expanding intervals just before it fades. Khan Academy’s practice lives inside each course; once you move on, nothing brings last month’s concepts back at the right moment. Study for six months without scheduled review and a large share of the early material is already gone, which is how people finish a course yet feel no better at maths. Consiliae schedules every mastered concept into spaced review automatically, so what you learn in week one is still there in month six.

The shelf that gets closest, and why it still is not a diagnosis

Khan Academy does have something adjacent to prerequisite routing. The Get Ready courses cover only the skills needed before entering the next grade, and a newer set of Math Essentials courses runs from grade 3 through precalculus. They are the closest the site comes to saying do this bit first. But they are anchored to grade levels rather than to concepts, which means they answer the question of what a student about to start grade 7 needs, not what this particular adult, who is fine with percentages and lost at negative exponents, needs. A grade is an average over a cohort. A prerequisite graph is a statement about one concept and the concepts it stands on, and only the second kind of structure can route around a gap that does not line up with anybody’s school year.

Closing the three gaps without paying anyone

This can all be done by hand, and if you are disciplined it works. For diagnosis: open the most advanced course you might plausibly know, take its course challenge cold, and drop down a course each time it goes badly. Write the failures down as a list of topics, because that list, and not the course name, is your actual curriculum. For sequencing: turn the list into an order by asking of each item what it needs underneath, and do the underneath ones first. For retention: keep a deck of problem types rather than facts, and re-do one old mastery challenge every week. The cost is not money. It is a few hours of planning up front, plus the ongoing discipline to maintain a schedule nobody else is maintaining for you. Plenty of people manage it. Most people who intend to, do not, and that gap between intention and Tuesday evening is the honest thing a paid product is selling.

The same comparison, in one table

So: is Khan Academy enough? For lessons, yes. For knowing where to start, what order to go in, and whether any of it sticks, it was never trying to be. Those three jobs are the product Consiliae is, and the two work perfectly well side by side. If you have concluded you want one tool doing all of it, our full comparison lays out that decision honestly.