GCD / LCM Calculator
Calculate the greatest common divisor (GCD) and least common multiple (LCM) of two or more integers.
How to use GCD / LCM Calculator: Open GCD / LCM 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.
Calculate the greatest common divisor (GCD) and least common multiple (LCM) of two or more integers. GCD / LCM 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 GCD / LCM Calculator
- Open GCD / LCM 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 GCD / LCM 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 gcd tasks are one click away.
Is it private and secure?
Your privacy is built in. GCD / LCM 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 GCD and LCM?
The greatest common divisor is the largest number dividing both values; the lowest common multiple is the smallest number both divide into. For 12 and 18, the GCD is 6 and the LCM is 36.
How are GCD and LCM related?
By the identity GCD(a,b) times LCM(a,b) equals a times b. That is how LCM is normally computed in practice — find the GCD with the Euclidean algorithm, then divide the product by it, which avoids overflow from multiplying first.
How does the Euclidean algorithm work?
Repeatedly replace the larger number with the remainder of dividing it by the smaller, until the remainder is zero; the last non-zero value is the GCD. It is over two thousand years old and still the standard method.
What are they actually used for?
GCD reduces fractions to lowest terms and appears throughout cryptography, notably in RSA key generation. LCM finds common denominators and answers scheduling questions — two events recurring every 12 and 18 days coincide every 36.
Related tools
See all free online calculators or browse the full tool catalogue.