Calculus
Integral Calculator
Approximate definite integrals between any two bounds or evaluate an antiderivative numerically at a point.
Approximate definite integrals or evaluate an antiderivative at a point.
Integral definition
∫_a^b f(x) dx
The calculator applies adaptive Simpson’s rule behind the scenes, making it ideal for smooth functions. For indefinite results it integrates from 0 to x and reports F(x) + C.
How to use
- Enter the function f(x) using x as the variable (sin, cos, log, exp, etc. are supported).
- Choose definite mode to supply lower and upper bounds, or indefinite mode to evaluate F(x) at a point.
- Review the approximation plus any helpful context such as the evaluation point or bounds.
Example
Input: f(x) = x^2, a = 0, b = 2
Output: ∫₀² x² dx ≈ 2.6667
FAQ & notes
Which functions are supported?
Standard JavaScript math functions (sin, cos, tan, exp, log, sqrt, etc.) are supported. Use ** for powers or write expressions like x^2 which are automatically converted.
How accurate is the result?
Simpson’s rule converges quickly for smooth functions. Increase precision by rewriting the function if it has discontinuities at the bounds.