# GCF and LCM Calculator

> GCF and LCM calculator: find the greatest common factor and least common multiple of two or more numbers instantly. Free, runs in your browser, no signup.

- **Canonical URL:** https://boringtoolskit.com/gcf-lcm-calculator/
- **Category:** Everyday Calculators
- **Evidence level:** authored-methodology
- **Reviewed:** August 2026
- **Last verified:** 2026-10-12
- **Privacy:** Inputs and results stay in this browser unless the page clearly labels an external request.

## How it works

GCF: largest integer dividing both numbers (Euclid). LCM = a x b / GCF.

## Worked example

For 12 and 18: GCF 6, LCM 36.

## Sources

- [Calculation methodology and verification standard](/methodology/)

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