The diagnostic on freepracticeSAT.com is a full 44-question SAT Math test in two 35-minute modules. It is free, there is no credit card, and an account takes under a minute. When you finish you get an estimated score out of 800, your results in the four SAT math areas, and a look at the specific mistakes behind your wrong answers.
I built this because a score on its own does not help a student much. When a student tells me "I got a 560," my next question is always the same: which 560? Two students with that score can need completely different things. One never learned how exponents work. The other knows the math and loses points to careless setup. A diagnostic should tell those two students apart.
Plan on about 80 minutes with the break. Keep pencil and paper next to you and work each problem out properly. If you rush through it, the results will describe your rushing and not your math.
A lot of practice tests mark a question wrong and stop there. But the wrong answer you chose tells me what you were thinking. Here is a small example of how I write the choices. The question asks for the midpoint of the segment from $(2, 1)$ to $(8, 7)$. The answer is $(5, 4)$.
| If you picked | This is probably what happened |
|---|---|
| $(6, 6)$ | You subtracted the coordinates, which is the first step for slope or distance. |
| $(10, 8)$ | You added the coordinates, which is right, but forgot to divide by $2$. |
| $(3, 3)$ | You found half the distance between the points and did not start from an endpoint. |
An example written for this page.
All three students got the question wrong, and all three need a different conversation with their teacher. So I tied the wrong answers on my tests to named mistakes. Underneath those are the 280 basic skills I call the DNA of SAT math questions, going back as far as Grade 5. A student who keeps missing slope questions may not have a slope problem at all. It may be fractions.
I looked at the first full test of every student on this site who answered at least 35 of the 44 questions, from May 30 to November 4, 2026. The student in the middle scored 700 and missed 8 questions. The middle number of different mistakes was also 8, so almost every miss had its own cause.
I find that useful. A student who misses 8 questions usually does not have one big problem. They have 8 small ones, and more random practice will only stumble across some of them. These were the mistakes the most students made:
| Mistake | Students | Share |
|---|---|---|
| Assumes a ratio changes when a figure is scaled up or down | 138 | 61% |
| Matches the wrong side to the wrong angle in a $30°$-$60°$-$90°$ triangle | 103 | 45% |
| Leaves out $\sqrt{2}$, or adds only two sides, in the perimeter of an isosceles right triangle | 94 | 41% |
| Treats $\sin^2\theta + \cos^2\theta$ as $(\sin\theta + \cos\theta)^2$ | 77 | 34% |
| Divides only some of the terms by the common factor | 72 | 32% |
| Confuses the input with the output when reading a rate of change | 72 | 32% |
Most of these students took the same first test, so this list reflects the questions on that test. It is not a ranking of the whole SAT. Students on my site also lean strong, so a middle score of 700 is not typical of all SAT takers.
You can take as many full tests as you like for free. From your second test on, how you do on Module 1 decides whether Module 2 is easier or harder, as on the real SAT.
A one-time payment of $29 builds a day-by-day plan to your test date from your own mistakes, with every mistake worked out and the Desmos video walkthroughs. You don't need it to use the diagnostic. You can see a sample plan first.
I built this one, so I am not a neutral judge. Here is what the others say about themselves as of November 2026.
| Option | Math questions | Score | What the report tells you |
|---|---|---|---|
| freepracticeSAT.com | 44, full math section | Estimated, out of 800 | Four math areas, pacing, and the mistakes and basic skills behind your misses |
| Bluebook (College Board) | Full official test | Official practice score | Every question with an explanation, in My Practice |
| Galvanize | Part of 25 questions across both sections | Predicted, out of 1600 | Section scores and accuracy by topic |
| Magoosh quiz | 10, of 21 in all | None, not meant to predict a score | Results and an explanation for each question |
Details change, so check each site before you rely on them.
If you only have time for one thing, take an official Bluebook test. Nothing else is as close to test day, and my score is an estimate, not a College Board score. Mine is for the next step: finding out why you lost those points. I wrote more about using both in freepracticeSAT.com or Bluebook.
Yes. The test and the results above cost nothing, and I don't ask for a card. The only paid product on this site is the plan.
As early as you can. A diagnostic is most useful when there is still time to act on it. If your SAT is only days away, take it anyway, then spend your time on the first mistakes it shows you.
The results go to the student's account and email. The simplest way is to sit down together and look at them. The four math areas are a good place to start that conversation.
There is a 5-question sample on the home page, with no account needed. It gives you a feel for the questions, but five questions can't diagnose anything.
The test takes about 80 minutes. Bring a pencil and paper.
Take the free diagnosticWhere these facts come from: