Khan Academy for SAT Math: it is free, official, and it covers the whole test. Sigma Prep is $49 a month, Math only, and built around one thing Khan does not do: a video walkthrough on every problem you miss, with fresh practice made from those misses. If you are starting from scratch or need Reading and Writing, use Khan. If your Math score is stuck and you have already done Khan, that is what Sigma Prep is for.
We build Sigma Prep, so read this with that in mind. The table is factual and the rows where Khan wins are stated plainly.
Side by side, as of September 2026
| Sigma Prep | Khan Academy | |
|---|---|---|
| Price | $49 per month, cancel anytime, 14-day money-back guarantee | Free |
| Sections | Math only; Reading and Writing is in the works | Reading and Writing plus Math |
| Official status | Independent, built by a tutor | College Board's official practice partner |
| Practice problems | 7,000+, all SAT-style, organized by the 19 College Board skills and by Easy, Medium and Hard | Broad math practice across topics, personalized from your PSAT or Bluebook results |
| Full-length tests | 24 Math tests: 8 mirrors of official tests, 3 versions each, two-module adaptive; first one free | None of its own; it points you to the 8 free Bluebook tests |
| Explanations | A video on every problem, plus topic video lessons | Written explanations and video lessons by topic; no walkthrough per problem |
| Desmos | Built into every practice question and test; most video solutions use it | Little coverage of the built-in calculator |
| After a miss | A practice set built from the questions you missed, same skills, new problems | Suggested topic practice |
| Progress for parents | Parent view: problems done, accuracy by topic, test scores over time | Parent accounts with activity reports |
| Score accuracy | Estimated 200 to 800 range from a mirrored test | Real scores come from Bluebook, not Khan |
Where Khan Academy wins
It is free, it covers both sections, and it is the official partner, so its content matches what College Board wants you to know. If money is tight or you have not started prep at all, there is no reason to pay anyone before you have used Khan and the free Bluebook tests.
Where Sigma Prep wins
Depth on the Math section. Every one of the 7,000+ problems is a variation of an SAT question type, filed under its skill and difficulty, so a student who keeps missing hard linear-function questions can drill exactly that. Every miss has a video showing the fast way, usually in Desmos, and the app builds the next practice set from what you missed. Khan tells you the answer; Sigma Prep shows you the move.
What Sigma Prep does not do
No Reading and Writing yet. It is being built now and is not available at the moment. No official scoring, our test scores are estimates from mirrored tests. No live classes inside the subscription; those are separate. If you need any of those, Khan Academy and Bluebook are the right tools and they are free.
Who should use which
- Starting from zero, or scoring under 500 in Math: Khan Academy first, then Bluebook. Add Sigma Prep when you can take a practice test and name the topics you keep missing.
- Stuck between 550 and 700 after using Khan: Sigma Prep. The gap at this level is repetition on the exact types you miss and Desmos fluency, which is what the platform is built around.
- Chasing 750 to 800: Sigma Prep's hard sets and the 24 tests for fresh full-length measurement, plus the free Bluebook tests for the official score.
Try the free diagnostic, twelve real SAT Math questions, no card, or take the free full-length practice test with a free account.