Find the greatest common factor (GCF) of two or more numbers.
How greatest common factor is worked out
Enter numbers to get their greatest common factor, along with the least common multiple. The GCF is the largest number that divides them all.
Using the calculator
- Enter your figures in the fields provided.
- The result updates as you type.
- Review the breakdown below the main number.
The maths behind it
GCF via the Euclidean algorithm
Worked example
Worked through, a numbers of 12, 18, 24 produces a GCF of 6. Alongside it, LCM comes out at 72. Change any field and every figure updates as you type.
Common questions
What is the GCF?
The largest number that divides every input evenly.
Why is the GCF useful?
It simplifies fractions and factors expressions.