LCM and GCF Calculator
Find the Lowest Common Multiple (LCM) and Greatest Common Factor (GCF/HCF) of up to 6 numbers. Shows prime factorisation.
How to use the LCM & GCF
Enter your numbers
Type 2–6 numbers. The GCF (greatest common factor, also called GCD or HCF) and LCM (lowest common multiple) are calculated instantly. You can use 2 numbers for basic calculations or up to 6 for more complex ones.
What they mean
The GCF is the largest number that divides all the inputs exactly — useful for simplifying fractions and ratios. The LCM is the smallest number that all the inputs divide into — useful for finding common denominators and scheduling problems.
Frequently asked questions
Is the LCM & GCF free to use?
Yes, the LCM & GCF is completely free. There is no sign-up, no account required, and no limit on how often you can use it.
How accurate is the LCM & GCF?
The LCM & GCF uses standard mathematical formulas and produces results accurate to standard precision. For critical applications, always verify with an authoritative source.
What devices does the LCM & GCF work on?
The LCM & GCF works on any device with a modern web browser — desktop, laptop, tablet, or phone. It is mobile-friendly and works offline once the page has loaded.