What is GCF used for?

GCF is most commonly used to simplify fractions by dividing the numerator and denominator by their greatest common factor.

Can I find the LCM and GCF of more than two numbers?

Yes, enter any number of values and the calculator finds the LCM and GCF across the entire list.

LCM & GCF Calculator

Find the Least Common Multiple and Greatest Common Factor of two or more numbers

Enter Numbers (comma or space separated, 2 or more)

What are LCM and GCF?

The LCM (Least Common Multiple) is the smallest positive number that is a multiple of every number in your list. The GCF (Greatest Common Factor) — also called HCF (Highest Common Factor) — is the largest number that divides evenly into every number in your list. This calculator finds both instantly for two or more whole numbers.

How to Use the LCM & GCF Calculator

Enter two or more positive whole numbers, separated by commas or spaces.
Read the results — the LCM and GCF are calculated instantly as you type.

How LCM and GCF Are Calculated

GCF(a, b) is found using the Euclidean algorithm.
LCM(a, b) = (a × b) ÷ GCF(a, b)
For more than two numbers, the calculator applies these formulas pairwise across the whole list.

Example

For 12 and 18: the GCF is 6 (the largest number dividing both evenly), and the LCM is 36 (the smallest number both 12 and 18 divide into evenly).

Common Uses

GCF: Simplifying fractions to their lowest terms.
LCM: Finding a common denominator when adding or comparing fractions, or scheduling events that repeat at different intervals.

Frequently Asked Questions

GCF is most commonly used to simplify fractions — dividing both the numerator and denominator by their GCF reduces a fraction to its lowest terms.

Yes — enter as many numbers as you like, separated by commas or spaces, and the calculator finds the LCM and GCF across the entire list.