Greatest Common Factor Calculator
Find the largest positive whole number dividing every entered integer.
Your result
MATHEnter your values and select calculate.
On this page How it works & practical examples
How to use the Greatest Common Factor Calculator
Enter whole numbers separated by spaces, commas, semicolons or line breaks. The Euclidean algorithm repeatedly replaces a pair by a remainder calculation, then combines the result with the rest of the list. Negative inputs are treated by their absolute values. GCF is useful when reducing fractions or finding a common grouping size that fits several counts exactly.
The calculation
Worked example
The greatest common factor of 12, 18 and 24 is 6. The GCF of 0 and 18 is 18 under the usual non-zero convention.
Assumptions and limits
The tool supports up to 1,000 integers with magnitude at most one billion. An all-zero list is rejected because every positive integer divides zero and there is no greatest positive factor. Decimal measurements need to be converted to an agreed integer unit before entry; arbitrary decimal rounding would change the divisibility problem.
Common questions
Are GCF and GCD different?
They are names for the same greatest common factor or greatest common divisor.
Can I enter a negative number?
Yes. Its absolute value is used, because sign does not change the positive common divisors.