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- Math
- Reading
- Grammar
The ultimate guide to SAT mastery.
Deep Test Prep teaches every skill the SAT tests, with step-by-step walkthroughs, drawn explanations, and timed practice in a simulator that works like Bluebook.
The early-bird preorder is $97, one payment with no subscription. The price rises to $149 at launch, planned for Sunday morning, October 25, 2026.
A tour of the library
Watch a real SAT question get solved.
Each walkthrough marks up the question while it explains, one step at a time. The library has 96 of them.
Step-by-step walkthroughs
Watch a real SAT question get solved, one step at a time.
Each walkthrough reads the question with you, names the skill it tests, and checks every answer choice. A quick question after each step makes sure the idea stuck before you move on. The library has 96 of them so far.
Visual explanations
Every new idea comes with a drawing that shows what it means.
When a lesson uses a term like slope or independent clause, hover over it or tap it, and a card opens with a plain definition and a drawing of the idea. Worked examples mark the exact words or numbers that change, so you can see a rule at work instead of memorizing it.
- Grammar
independent clause
A group of words with a subject and a verb that makes sense by itself as a complete sentence.
Example"The bus was late" can stand alone.
- Math
slope
How steep a line is: how much y changes each time x goes up by 1. It is the m in y = mx + b.
Exampley = 3x + 2 rises 3 for every 1 step right.
- Reading
central idea
The main point of a whole passage: the one idea that everything else in it supports.
Desmos practice
Learn the Desmos skills that save time on SAT Math.
The practice room gives you a Desmos-style graphing calculator with a coach beside it. You type every equation yourself, and the coach checks each step and explains what the graph is telling you. Try the first lesson right here: graph both sides of an equation and find where they cross.
- Read a graph
- Work with tables
- Type with confidence
- Understand functions
Solve
What value of is the solution to the equation below?
1
Expression 1
2
Expression 2
Enter an equation to see its graph here
4 guided steps
Solve an equation
The two sides are equal where their graphs cross. That point's x-coordinate solves the equation.
You can also click anywhere in the calculator to begin. Type each expression with your keyboard.
Bluebook Simulator
Practice on a screen that works like test day.
Bluebook is the app you take the digital SAT in. Our simulator works the same way, with the same clock and the same tools, so test day feels familiar. Lesson practice opens in it, and you can try it now with 4 questions.
Test-day tools
Free, with 4 questions in 2 modules and 7 minutes on the clock
Countdown timer. The clock counts down the way it does on test day. Choose 1.5× or 2× time if you get extra time, and hide the clock whenever it distracts you.
10 or more Full-length practice tests
Each practice test runs in this simulator with the digital SAT’s full timing: 2 hr 14 min of testing across four modules, with a 10-minute break between the two sections.
- Reading and Writing
- Module 127 questions, 32 min
- Module 227 questions, 32 min
- 10-minute break
- Math
- Module 122 questions, 35 min
- Module 222 questions, 35 min
Practice-test insights
Every practice test shows where your time and attention went.
Your results compare your time on each question with the usual time and show where your mouse rested on every question.
Your results show your time on every question against the usual time
Each bar is one question. The shaded range is how long a prepared student usually needs. The tick is the shortcut time: how fast it goes when you already know the method, such as graphing in Desmos or spotting the grammar rule. Select a question to see what its time means.
Sample times
Question 11 · Evidence from texts, tables, and graphs
A long time, and still missed
You spent 2:53 where 0:55 to 1:35 is usual. When a question runs this long, choose your best answer, use “Mark for Review”, and come back if time is left.
Every skill mapped
All 122 lessons, grouped by the SAT section they help with.
Start with the section that costs you the most points. Each subject breaks into skill groups, and each lesson teaches one skill.
- 59lessonsSAT MathFor when you read a problem and don’t know where to start. Learn to set up the equation, spot the patterns the SAT reuses, and let Desmos check your work.Desmos MasteryAlgebra FoundationsProblem SolvingLinear RelationshipsFunctions+5 moreSee the SAT Math lessons
- 39lessonsSAT ReadingFor when two answer choices both sound right. Learn to follow the author’s point, find the line that proves an answer, and rule out choices that claim too much.ComprehensionVocabularyArgument & Critical ReadingText StructureRhetorical Analysis+4 moreSee the SAT Reading lessons
- 24lessonsSAT GrammarFor when comma and semicolon questions feel like a coin flip. Learn the sentence rules the SAT keeps testing and how to tell which one a question is about.Sentence StructurePunctuationTransitionsAgreementVerbs+2 moreSee the SAT Grammar lessons
XP and the weekly leaderboard
Every right answer earns XP, the moment you get it.
Lesson questions and “takeaways” give XP as soon as you get them right, and a wrong answer gets none. Full practice tests award XP with your results, for the habits that raise scores. On the weekly leaderboard, students appear only as a first initial and a picture they choose.
Free lessons
Try 16 full lessons free before you decide.
These lessons are open to everyone, so you can see exactly how the library teaches before you buy it.
SAT Math6 free
SAT Reading4 free
SAT Grammar6 free
Hello, I’m
Tom Meli
SAT instructor
I’ve spent twenty years learning how to explain hard ideas so they stick.
I’ve taught since 2006 and have focused on the SAT since 2015. Along the way, I’ve learned which explanations and examples help a student understand a difficult idea well enough to use it on a question they haven’t seen.
I built Deep Test Prep to put those lessons in one place. The online library covers SAT Math, Reading, and Grammar with step-by-step walkthroughs, drawn explanations, and practice that checks your thinking as you go.
When a question trips you up, you can open the lesson for that skill or work through a subject one topic at a time.
P.S. I’m also working to change how students learn in high school and beyond. You can see what I’m building next at Play for Mastery.
Deep Test Prep Online Library
Preorder now. Start studying at launch.
- 122 lessons across math, reading, and grammar
- 96 step-by-step question walkthroughs
- The Desmos practice room, with a coach for every step
- Plain definitions and drawings for key terms, right where you read them
- The Bluebook Simulator, with test-day timing and tools
- 10+ full-length practice tests
Early bird preorder
$97
One payment. No subscription.
Access begins at launch, planned for Sunday morning, October 25, 2026. Regular price: $149. No library access before launch.
See preorder detailsAlready have access? Sign in