Definite Integral Calculator
Evaluate a definite integral exactly where possible, numerically otherwise.
What is Definite Integral?
A definite integral is the signed area between a curve and the x-axis from a to b, and it is evaluated as F(b) − F(a) for an antiderivative F. It answers questions about totals: distance from a speed curve, charge from a current curve.
How it works
The exact antiderivative is attempted first and evaluated at the bounds; when the pattern is not recognised, Simpson's rule runs and the result is explicitly labelled numerical, with an error estimate. The page never presents an approximation as if it were the closed form.
- Enter your input. Type or paste your input into the field above — the tool responds instantly.
- Review the result. Output updates live as you type. Everything runs entirely in your browser.
- Copy or download. Use the Copy button to grab the result, or Download to save it as a file.
Examples
Realistic sample
Type or paste any realistic input — the tool computes the result locally and instantly.
Common mistakes
Expecting a server round-trip
Nothing is uploaded — every tool in this category runs entirely in your browser.