freepracticeSAT.com vs Khan Academy: Which One Should You Use for SAT Math?

By Dr. Brink, Ph.D., 32 years teaching mathematics

The short answer: use both, but for different jobs. Khan Academy is the place to learn a skill you don't know yet. freepracticeSAT.com is the place to take full timed tests and find out exactly which mistakes are costing you points.

Students ask me this question all the time, and my answer usually surprises them. These two sites aren't competing for the same slot in your week. One teaches. The other tests and diagnoses.

I'm biased, of course. I built freepracticeSAT.com. So I'll try to be fair to Khan Academy, which has helped millions of students and deserves its reputation.

What Khan Academy does well

Khan Academy is free, and it's excellent at teaching a skill you don't know yet. If you have never really understood systems of equations or exponential growth, Khan has short videos, step-by-step articles and practice exercises built around that one skill. You watch, you try a few problems, and you move on when you've got it.

Clear teaching videos for almost every SAT math topic
Skill-by-skill practice that lets you focus on one thing at a time
A mastery system that tracks which skills you've worked on
Completely free, with no ads

If you are starting from scratch, Khan Academy is a very good place to learn the math.

Where students get stuck

Here is a pattern I've seen for 32 years. A student practices one skill at a time, gets most of the questions right, and feels ready. Then they sit a full test and their score barely moves.

Two things happen on a real test that skill-by-skill practice doesn't copy:

The questions are mixed. On test day nobody tells you "this one is about slope." You have to recognize what a question is asking before you can solve it.
The clock is running. Answering 22 questions per module under time pressure is a different skill from answering 5 questions on a topic you just reviewed.

Khan Academy no longer offers full-length SAT practice tests. It sends students to College Board's Bluebook app, which has only a limited number of official tests. Many students run out of them weeks before their SAT. That's the gap freepracticeSAT.com was built to fill.

What freepracticeSAT.com does well

freepracticeSAT.com is built around full-length, realistic SAT math tests, and around telling you exactly why you're losing points.

Unlimited full-length tests. Two modules, 22 questions each, timed or untimed. You don't run out.
4,700 questions, written one by one. I wrote them myself. They're not scraped from other sites, and the bank is large enough that you keep seeing new questions.
Built-in Desmos and the formula sheet, just like the real digital SAT, so you practice with the same tools you'll have on test day.
Choose your difficulty. Easy, medium, hard or mixed. If you're aiming for 750 or above, you can practice only the hard questions.
A diagnosis, not just a score. After you've taken a couple of tests, the site names the specific mistakes you keep making (for example, "dividing only one term by the coefficient") and the basic skills underneath them that need work.

That last point matters most. A score of 560 tells you where you are. It doesn't tell you what to do on Monday. Knowing that most of your missed points come from three repeated mistakes and one weak foundation gives you a plan.

Side by side

	Khan Academy	freepracticeSAT.com
Best for	Learning a new skill	Testing yourself and finding your gaps
Full-length timed tests	None (sends students to Bluebook)	Unlimited
Teaching videos	Many	Worked solutions plus Desmos walkthroughs
Built-in Desmos and formula sheet	Not in a test setting	Yes, in every test
Choose difficulty	No	Easy, medium, hard or mixed
Names your repeated mistakes	No	Yes
Cost	Free	Tests free; full worked solutions and study plan are a one-time payment

How I'd use them together

If I were a junior with two months before the SAT, this is what I'd do:

Take a full timed test on freepracticeSAT.com. That's your starting point.
Read your diagnosis. Write down the three mistakes that cost you the most points.
Go to Khan Academy for any skill you don't understand at all. Watch the video and do the practice set.
Come back for another full test about once a week. Check whether those three mistakes have shrunk.
In the last two weeks, switch to mostly full tests, ideally at the same time of day as your real SAT.

Khan Academy fills the holes in your knowledge. freepracticeSAT.com shows you where the holes are and whether you've filled them.

The bottom line

If you only have time for one, pick based on where you are:

You don't know the math yet: start with Khan Academy.
You know the math but your score is stuck: you need full tests and a diagnosis. Start with freepracticeSAT.com.

Most students I meet are in the second group. They've done plenty of practice. What they're missing is someone telling them precisely what keeps going wrong.

Dr. Brink
Ph.D. in Mathematics Education, 32 years teaching math

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