This is an online common factors calculator that computes the common factors of two or more positive integers. First, a lists of all factors of each number is displayed then a list of the commom factors to all these positive integers is displayed.
What is a factor of a number?
A number n is a factor of another number N if the division

N ÷ n

gives a remainder equal to zero.
3 is a factor of 6 because 6 ÷ 3 = 2 and the remainder is equal to 0.
3 is NOT a factor of 7 because 7 ÷ 3 gives a remainder equal to 1.
n is a factor of N also means that we can write N as a product (multiplication) of n and another number.
3 is a factor of 6 because 6 = 3 × 2.

Example
The factors of each of the positive integers 12,18,30 are:
The factors of 12 are: 1,2,3,4,6,12
The factors of 18 are: 1,2,3,6,9,18
The factors of 30 are: 1,2,3,5,6,10,15,30
The factors in red are the common factors to all three numbers are therefore are listed below.
The common factors of 12,18,30 are:,1,2,3,6
and of course we may also deduce the greatest common factor (GCF) of the three numbers which in this case is 6.

Use Common Factors Calculator

We can use this calculator to factor numbers, fincd their common factors and fing the greatest common factor (GCF) to all entered numbers.
Enter the positive integers N1, N2, ... Nn separated by commas and then press "Calculate Common Factors".