Interactive Digital SAT maths tools
Graphers and diagrams for the topics where a picture does the explaining. Free, no account, nothing to download — and every answer is exact rather than a rounded decimal, because the grid-in wants the exact value.
They are all drawn by one engine, and it is open on its own page: the graphing calculator, where you type any equation and tap a curve for its points. For the questions with no answer choices, how to enter an answer shows every form the box accepts, and the score range tool turns practice totals into the range to expect, and the reference sheet, explained lists what the test hands you and what it assumes you know. For Reading and Writing there is the Sentence Lab, which shows which punctuation is legal at a slot and why.
Interactive Systems of Equations Grapher & Solver
Available nowA system of two linear equations has one solution, no solution, or infinitely many — and which one it is depends only on whether the two lines have the same slope, and if they do, whether they are the same line. Drag either line below and watch the count change.
Open the toolInteractive Parabola Grapher: Vertex, Standard and Factored Form
Available nowA parabola's three forms are the same curve written three ways, and each one hands you a different fact for free: vertex form gives the vertex, factored form gives the roots, standard form gives the y-intercept. Move the sliders below and watch all three rewrite themselves at once.
Open the toolInteractive Margin of Error Calculator: Sample Size vs. Confidence
Available nowA margin of error doesn't shrink in proportion to your sample size — it shrinks with the square root of it, so doubling your respondents narrows the interval by only about 30%, and it takes four times the sample to actually cut the margin in half. Drag the slider below and watch the exact numbers move.
Open the toolInteractive Percent Change Calculator: Why 20% Up and 20% Down Isn't 0%
Available nowA rise and an equal fall never cancel, because the fall is a percentage of a different, larger amount than the rise was. Raise 500 by 20% and it becomes 600; fall by 20% from there and it lands at 480, not 500. Drag both percent changes below and watch exactly where it lands.
Open the tool
What is coming
4 of 22 graphable topics on the Digital SAT maths syllabus have a public tool. The rest are listed here rather than published as empty pages — each one ships when there is a working simulation behind it and the maths has been written out.
- Slope as a rate; what m and b each do to a lineAlgebra
- Standard, slope-intercept and point-slope as one lineAlgebra
- Half-plane shading, strict versus inclusive edges, systems as overlapAlgebra
- Exponential growth and decay against linear changeAdvanced Math
- Function transformations: f(x-h)+k, af(x), f(-x) on one parent curveAdvanced Math
- Polynomials: degree, end behaviour and root multiplicityAdvanced Math
- Rational functions: vertical asymptotes, holes and end behaviourAdvanced Math
- Absolute value and radical functions, including domain restrictionsAdvanced Math
- A line meeting a parabola: two, one or no solutionsAdvanced Math
- Fitting a line to a scatter, and where prediction stops being evidenceProblem-Solving and Data Analysis
- Dragging an outlier: what moves the mean but not the medianProblem-Solving and Data Analysis
- Proportional relationships as lines through the originProblem-Solving and Data Analysis
- Two-way tables as areasProblem-Solving and Data Analysis
- Similar right triangles and the Pythagorean relationshipGeometry and Trigonometry
- Arcs and sectors as a fraction of the whole circleGeometry and Trigonometry
- The equation of a circle, and completing the square to find itGeometry and Trigonometry
- The unit circle: sine and cosine as coordinatesGeometry and Trigonometry
- How scaling one dimension changes area and volumeGeometry and Trigonometry
Something missing that a picture would fix? Ask for it, or read how the rest of Preptics works.
SAT® is a trademark registered by the College Board, which is not affiliated with, and does not endorse, this site. All practice questions and reading passages are original works created by Preptics and are not actual SAT® questions.