Common Factor Calculator
Find all common factors of two or more integers — every number that divides all of them evenly.
How to use the Common Factor Calculator
- Enter your inputs into the Common Factor Calculator above.
- Results update instantly as you type — no submit button needed.
- Adjust any value to see how the result changes in real time.
The common factors approach
Common factors of (a, b, ...) = factors of GCD(a, b, ...)
The factors common to multiple numbers are exactly the factors of their greatest common divisor. So find the GCD, then list all factors of that GCD.
Worked example
Common factors of 24 and 36: GCD is 12. Factors of 12: 1, 2, 3, 4, 6, 12. Common factors of 18, 24 and 60: GCD is 6. Factors: 1, 2, 3, 6.
Frequently asked questions
How is this different from GCF?
GCF is the single largest common factor. "Common factors" is the complete list. GCF is the largest entry in the list.
Can two numbers share no common factor?
Two numbers always share 1 as a common factor. If 1 is the only common factor, the numbers are coprime (or relatively prime).
How does this help with fractions?
When simplifying a fraction, you divide top and bottom by any common factor. The fraction is fully simplified when the only common factor is 1.