

How to Calculate Common Factors Step by Step
What is Common Factor Calculator?
A Common Factor Calculator helps you find all factors shared by two or three numbers instantly online. It works for homework, exams, or practice, making math tasks faster and easier for all students.
This calculator eliminates manual factor listing. Just input your numbers to see a detailed factorization and discover all shared divisors in seconds.
Formula Behind Common Factor Calculator
To determine common factors, first list all factors for each number. The shared factors, meaning those present in every list, are the common factors. In set notation: Common Factors = F(A) ∩ F(B) ∩ F(C), where F(X) is the set of factors for integer X.
Common Factor Table (Examples)
Numbers | Factors of Each | Common Factors |
---|---|---|
12, 18 | 12: 1, 2, 3, 4, 6, 12 18: 1, 2, 3, 6, 9, 18 |
1, 2, 3, 6 |
8, 20 | 8: 1, 2, 4, 8 20: 1, 2, 4, 5, 10, 20 |
1, 2, 4 |
15, 25, 35 | 15: 1, 3, 5, 15 25: 1, 5, 25 35: 1, 5, 7, 35 |
1, 5 |
9, 28 | 9: 1, 3, 9 28: 1, 2, 4, 7, 14, 28 |
1 |
24, 36 | 24: 1,2,3,4,6,8,12,24 36:1,2,3,4,6,9,12,18,36 |
1,2,3,4,6,12 |
Steps to Use Common Factor Calculator
- Enter two or three integers in the input box, separated by space or comma.
- Click the "Find Common Factors" button to process.
- Review all individual factor lists and the common factors shown instantly below.
Why Use Vedantu’s Common Factor Calculator?
Vedantu's Common Factor Calculator is ideal for exam prep and assignments, producing accurate results with stepwise explanations. It's designed for students to save time over manual calculations and is free and accessible anytime online.
This tool automatically shows each number’s factors and cleanly lists all common factors. With its simple interface, students from CBSE, ICSE, or any board can confidently solve problems on HCF, simplification, or basic number theory in seconds. You can also explore advanced tools like the HCF Calculator and Prime Numbers resources.
Applications of Common Factor Calculator
Finding common factors is essential in reducing fractions, solving algebraic expressions, and determining HCF/LCM. Students use this concept frequently in school mathematics as well as competitive exams and Olympiads.
This concept also has applications in simplifying ratios and working out shared groupings, making it useful beyond classroom maths. You can learn more about related concepts with our detailed pages on Multiples in Maths or discover Factors of Numbers across topics. To advance your learning in algebraic factorization, try our Algebra Topics as well.
FAQs on Find Common Factors of Numbers – Free Calculator Tool
1. How does the online Common Factors Calculator work?
Vedantu's Common Factors Calculator is a free online tool designed for speed and accuracy. To use it, simply enter two or more numbers into the designated input fields and click the 'Calculate' button. The tool instantly processes the numbers by listing all factors for each one and then identifies and displays the factors that are common to all the numbers you entered.
2. What are common factors in mathematics?
Common factors are the numbers that can divide two or more different numbers exactly, without leaving a remainder. For instance, to find the common factors of 12 and 16:
- The factors of 12 are 1, 2, 3, 4, 6, and 12.
- The factors of 16 are 1, 2, 4, 8, and 16.
3. How do you find all common factors of 18 and 24?
To find all common factors of 18 and 24, you first list the individual factors for each number.
- Factors of 18: 1, 2, 3, 6, 9, 18.
- Factors of 24: 1, 2, 3, 4, 6, 8, 12, 24.
4. What is the difference between a common factor and the Greatest Common Factor (GCF)?
The key difference lies in what they represent. Common factors are all the numbers that can divide a set of numbers. In contrast, the Greatest Common Factor (GCF), also known as the Highest Common Factor (HCF), is the single largest number among those common factors. For example, while 1, 2, 3, and 6 are all common factors of 18 and 24, the GCF is just 6.
5. How can you find common factors quickly for exams?
The quickest way to find common factors, especially for larger numbers, is the prime factorization method. First, break down each number into its prime factors. Then, identify the prime factors that are common to all the numbers. The product of these shared prime factors, in all their combinations, gives you the common factors. For speed during practice, a calculator tool is excellent, but for exams, mastering prime factorization is the most efficient manual method.
6. Can a pair of numbers have only one common factor?
Yes, absolutely. Every pair of integers has at least one common factor, which is 1. When 1 is the only common factor between two or more numbers, those numbers are called coprime or relatively prime. For example, the numbers 8 and 15 are coprime because their factors (Factors of 8: 1, 2, 4, 8; Factors of 15: 1, 3, 5, 15) only have 1 in common.
7. Why is finding common factors an important skill in maths?
Finding common factors is a fundamental skill in mathematics primarily because it is the basis for simplifying fractions. By dividing both the numerator and the denominator by their Greatest Common Factor (GCF), you can reduce a fraction to its simplest form. This concept is crucial for more advanced topics in algebra, such as factoring polynomials and solving equations.











