Free AP Calculus AB and BC

Calculus you can drag.

Solvers hand you an answer and paywall the steps. Here, every core idea is something you move: drag a point and the derivative draws itself, slide n and the rectangles become the integral, shrink h and the secant becomes the tangent. The one below is real. Try it.

\int_{0}^{2} x^2\,dx = 2.6667
left sum 2.1875, exact integral 2.6667, error 0.4792. The left sum is an underestimate here.
left sum, n = 8
2.1875
exact integral
2.6667
error
0.4792
Error (log scale)The left sum is an underestimate here

Full bar is the worst single-rectangle error for this function; empty means the sum is within 0.0001 of the exact integral.

That is a Riemann sum becoming an integral, live. Every visualizer and calculator on this site works like this.

Everything here moves

5 visualizers and 12 teaching calculators. None of them are black boxes: you do the thinking step, the tool checks it and shows the why.

Visualizer

Tangent Line Tracer: Watch the Derivative Appear

Drag a point, watch the derivative draw itself

Visualizer

Riemann Sum Slider: Drag n, Watch the Error Vanish

Drag n and watch the rectangles become the integral

Visualizer

Secant to Tangent: The Limit Definition, Made Physical

Shrink h to zero with your own hands

Visualizer

Solid of Revolution Builder: Disk, Washer, and Shell

Spin a region into a 3D solid

Visualizer

Related Rates Scene: Sliding Ladder and Cone Tank

Slide the ladder, see both rates move

Teaching calculator

Riemann Sum Visualizer: Rectangles, Error, and Rules

Your f(x), your bounds, every method

Teaching calculator

Chain Rule Step Trainer: You Pick the Decomposition

You spot the composition, it checks you

Teaching calculator

U-Substitution Helper: Pick u, See Why It Works

Pick u, get told why it works or stalls

Teaching calculator · BC

Series Convergence Test Chooser: Which Test and Why (BC)

Walk the decision tree question by question

Teaching calculator

Limit Solver (Teaching Mode): Which Method and Why

Which limit technique, and why

Teaching calculator

Definite Integral Step Tool: FTC, Shown Honestly

The antiderivative and bounds, step by step

Teaching calculator

Tangent and Normal Line Finder (Teaching Mode)

Tangent and normal lines with the work shown

Teaching calculator · BC

Taylor Series Builder: Coefficients from Derivatives

Add terms, watch the polynomial hug the curve

Teaching calculator

Derivative Practice Checker: Any Correct Form Passes

Type any correct form, it knows

Teaching calculator

Related Rates Setup Builder: The Five-Step Method

You pick the relation, it scaffolds the rest

Teaching calculator

Optimization Setup Builder: Objective vs Constraint

Objective vs constraint, the setup skill

Teaching calculator · BC

Interval of Convergence Finder: Ratio Test and Endpoints

Ratio test plus honest endpoint checks

From the maker of EconLearn, which the Colorado Department of Education lists in its economics resource bank.

Start with the course

Both courses follow the official College Board framework, unit by unit, with exam weightings from the current Course and Exam Description.

Or jump to what is due tonight

Method guides for the questions solvers cannot answer: which technique, how to set it up, and why it works.