What are LCM and GCF?

LCM (Least Common Multiple) is the smallest number divisible by all given numbers; GCF (Greatest Common Factor) is the largest number dividing evenly into all of them.

How is GCF calculated?

Commonly via the Euclidean algorithm, or by comparing prime factorizations of each number.

Where are LCM and GCF used practically?

LCM helps add fractions with different denominators; GCF helps simplify fractions to lowest terms.

LCM & GCF Calculator - CalculatorLabs.net

LCM & GCF Calculator

Find the Least Common Multiple and Greatest Common Factor of any list of numbers.

Numbers (comma-separated)

Greatest Common Factor (GCF)-

Least Common Multiple (LCM)-

What Is an LCM & GCF Calculator?

The Greatest Common Factor (GCF, also called GCD) is the largest number that divides evenly into every number in a list. The Least Common Multiple (LCM) is the smallest number that all of them divide into evenly. These are essential for simplifying fractions, finding common denominators, and solving ratio problems.

The GCF lives in the overlap of both numbers' factors.

Formula

GCF found using the Euclidean Algorithm
LCM(a, b) = (a × b) ÷ GCF(a, b)

How to Use This Calculator

Type two or more whole numbers, separated by commas.
Click "Calculate LCM & GCF".
Read off the greatest common factor and least common multiple for your full list of numbers.

Worked Example

Example: For 12 and 18: GCF = 6 (largest number dividing both), LCM = (12 × 18) ÷ 6 = 36 (smallest number both divide into).