Integral Calculator
Compute definite and indefinite integrals of functions.
How to use Integral Calculator: Open Integral Calculator in your browser — it loads instantly and works offline once cached. Enter your values in the input fields. Every field is labelled so you know exactly what to type. The result updates automatically as you type — there is no "submit" round-trip to a server. Everything runs inside your browser, so your data never leaves your device.
Numerical definite integral via Simpson's rule (1000 intervals). Trig uses radians.
Compute definite and indefinite integrals of functions. Integral Calculator is a free, browser-based tool in the Filevane math calculators collection — there is nothing to install, no account to create and no watermark on your results. It works on desktop, tablet and mobile, and because the work happens on your own device it stays fast even with large inputs.
How to use Integral Calculator
- Open Integral Calculator in your browser — it loads instantly and works offline once cached.
- Enter your values in the input fields. Every field is labelled so you know exactly what to type.
- The result updates automatically as you type — there is no "submit" round-trip to a server.
- Adjust any input to compare scenarios and see how the outcome changes in real time.
- Copy or note the result. Nothing you enter is stored or sent anywhere.
Why use Integral Calculator?
- 100% free with no limits, no sign-up and no watermarks.
- Private by design — your data are processed in your browser and never uploaded to a server.
- Fast and lightweight, with instant results even on a phone or a slow connection.
- Works everywhere — any modern browser on Windows, macOS, Linux, Android or iOS.
- Part of a full math calculators suite, so related integral tasks are one click away.
Is it private and secure?
Your privacy is built in. Integral Calculator runs completely on your device, so whatever you enter stays in your browser and is never transmitted, logged or stored on any server.
Network activity: none. Nothing is sent and nothing is fetched. This tool makes no network request at all once the page has loaded — which is why it keeps working if your connection drops.
You do not have to take that on trust — our privacy proof page publishes the Content-Security-Policy that enforces it, lists every third party it permits, and shows how to verify the whole claim yourself.
Learn more
Why Browser-Based Tools Are Safer for Your Files — Most online converters upload your files to a server. Client-side tools don't. Here's why that difference matters for privacy.
Frequently asked questions
What is the difference between a definite and an indefinite integral?
An indefinite integral is the family of antiderivatives and carries a constant of integration, + C. A definite integral has limits and evaluates to a number — the signed area under the curve between them.
Why does the constant of integration matter?
Because differentiation destroys constants: the derivative of x² and of x² + 7 are identical. Reversing the operation cannot recover which constant was there, so + C represents every possible answer until a boundary condition pins it down.
Why can some functions not be integrated symbolically?
Because their antiderivative is not expressible in elementary functions. e^(-x²) is the famous case — central to statistics, yet its integral requires the error function erf(x), which is defined precisely because no elementary form exists. Such cases need numerical integration.
What does a negative definite integral mean?
That more of the curve lies below the axis than above it between those limits. If you want geometric area rather than signed area, integrate the absolute value, or split the interval at each crossing point.
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