GCF Calculator

Use our free GCF calculator to find the greatest common factor of two or more numbers, view all common factors, and see the paired LCM.

Math

Mode

Numbers

Formula

The greatest common factor (GCF) is the largest positive integer that divides every number in a set. Also known as the greatest common divisor (GCD) or highest common factor (HCF).

GCF is the largest positive integer that divides all given numbers without a remainder.

Percentage: The percentage value you want to apply

Number: The original number or value

Result: The calculated result

How It Works

1Select a mode: basic GCF, with common factors, or paired with LCM.
2Enter two or more numbers separated by commas.
3Click Calculate to see the GCF.

Examples

GCF of 12, 18

1.Factors of 12: 1,2,3,4,6,12
2.Factors of 18: 1,2,3,6,9,18
3.Common: 1,2,3,6
4.GCF = 6

Result: 6

GCF+LCM of 12, 18

1.GCF=6
2.LCM=36
3.GCF × LCM = 216 = 12×18

Result: 6

GCF of 7, 11

1.Both prime — only common factor is 1
2.Coprime numbers

Result: 1

Frequently Asked Questions

The largest number that divides all given numbers evenly.

They are the same concept with different names.

The numbers are called coprime or relatively prime.

Compute pairwise: GCF(a,b,c) = GCF(GCF(a,b), c).

The GCF is always positive.

Related Calculators

GCD Calculator LCM Calculator Factors Calculator Divisibility Calculator Percentage Calculator Basic Calculator

CalculateMe Team

Last updated: 2026-07-14

GCF Calculator

Formula

How It Works

Examples

GCF of 12, 18

GCF+LCM of 12, 18

GCF of 7, 11

Frequently Asked Questions

What is GCF?

GCF vs GCD?

What if GCF is 1?

GCF of more than 2 numbers?

Can I use negative numbers?

Related Calculators

GCF Calculator

Formula

How It Works

Examples

GCF of 12, 18

GCF+LCM of 12, 18

GCF of 7, 11

Frequently Asked Questions

What is GCF?

GCF vs GCD?

What if GCF is 1?

GCF of more than 2 numbers?

Can I use negative numbers?

Related Calculators