Common Factor Calculator

Find all common factors (divisors) of two or more positive integers.

Enter two or more numbers separated by commas (e.g., 12, 18, 24)

Understanding Common Factors

Common factors are positive integers that divide two or more numbers without a remainder. The greatest common factor (GCF), also known as the greatest common divisor (GCD), is the largest such number.

What are Factors?

Factors (or divisors) of a number are integers that divide the number evenly without a remainder. For example, the factors of 12 are 1, 2, 3, 4, 6, and 12.

How to Find Common Factors:

  1. List all factors of each number individually
  2. Identify the factors that appear in all lists
  3. These shared factors are the common factors
  4. The largest number in this list is the Greatest Common Factor (GCF) or Greatest Common Divisor (GCD)

Examples of Common Factors:

Example 1: Find common factors of 12 and 18

  • Factors of 12: 1, 2, 3, 4, 6, 12
  • Factors of 18: 1, 2, 3, 6, 9, 18
  • Common factors: 1, 2, 3, 6
  • GCD = 6

Example 2: Find common factors of 24, 36, and 48

  • Factors of 24: 1, 2, 3, 4, 6, 8, 12, 24
  • Factors of 36: 1, 2, 3, 4, 6, 9, 12, 18, 36
  • Factors of 48: 1, 2, 3, 4, 6, 8, 12, 16, 24, 48
  • Common factors: 1, 2, 3, 4, 6, 12
  • GCD = 12

Applications of Common Factors:

In Mathematics:

  • Simplifying fractions to lowest terms
  • Solving Diophantine equations
  • Computing the Least Common Multiple (LCM)
  • Calculating proportions and ratios
  • Finding common denominators

Practical Applications:

  • Dividing items equally into groups
  • Determining common intervals or cycles
  • Simplifying measurements
  • Calculating gear ratios
  • Computer algorithm optimizations

Advanced Methods for Finding GCD

  • Euclidean Algorithm: An efficient method that uses successive division to find the GCD without listing all factors.
  • Prime Factorization: Finding the GCD by identifying common prime factors shared by all numbers.
  • Stein's Algorithm: A binary GCD algorithm that replaces division with simpler operations like shifting and subtraction.
  • Extended Euclidean Algorithm: An extension that computes the coefficients of Bézout's identity in addition to the GCD.

How to Use the Calculator:

  1. Enter two or more positive integers separated by commas in the input field
  2. Click "Find Common Factors" to calculate the result
  3. View all common factors and the Greatest Common Divisor (GCD)
  4. See additional statistics about the common factors