About the Integral Calculator

A definite integral and antiderivative calculator, in your browser.

What it is

The Integral Calculator computes the definite integral of a function over an interval using Simpson's rule, a highly accurate numerical integration method. For polynomial functions and 1/x, it also derives the symbolic antiderivative using the power rule and natural log rule, then verifies the numeric result using the Fundamental Theorem of Calculus.

Features

Simpson's rule integration

Accurate numeric integration for any function math.js can parse.

Symbolic antiderivatives

Power rule and natural log rule antiderivatives for polynomial and 1/x functions.

Quick-start presets

Common example functions to load with one click.

Step-by-step working

See the antiderivative and the Fundamental Theorem of Calculus substitution when available.

Ready to use it?

Free, no sign-up required.

Open the Integral Calculator